Lacks power after driving on highway for bout 15 min

[entity-unknown]

I have a very odd issue. My truck runs great almost all the time. My main issue is when I'm driving on the highway in 4th gear at or over 2200 RPM's for about 15 to 20 minutes, my truck sort of jerks a bit and then starts to slow down. I can hold about 2000 - 2100 RPMs in any gear but I have no acceleration. If I try to accelerate it will make a sound like a backfire or clanking. I've only tried to accelerate hard twice so I couldn't totally place the sound since I didn't want to make it any worse. When I have to stop, then go again, there is still no power/acceleration through any gear and it takes me about 1 minute to get up to regular posted speeds. If I shut the truck off for about 15 minutes, I can drive perfectly forever, unless I go back up to 4th gear above 2000 RPM, then I'm back to the issue. If I let it sit for about 30 minutes, I can go the full 15 - 20 minutes again. During this time I can also go in Neutral or Park (No I didn't try on the highway only while stopped) I can rev the engine and it responds perfectly. To me it seems like losing pressure in the transmission, being starved of fuel, or a seal giving, but definitely revolves around heavy load or high pressure for a prlonged period of time. Should be simple huh? :|

I also have a slightly hard shift into 4th gear if I'm at a medium or slow acceleration. Mild and hard accelerations almost always give a smooth shift. 2nd gear also has a pretty rough shift typically and sometimes has exhibits almost the same lack of power, as well the backfire/clank sound. There is also a rare rough shift into reverse and sometimes drive. Drive is pretty smooth now after adjusting the TVC so I'm gonna probably gonna try adjusting this again. There's also a clunk when the shifting into drive or reverse as well but I'm sure that one is u-joints so I'm gettin to those this weekend as well. The truck shudders at speeds over 2200 RPMs as well.

The truck sat for about 3 years, cuz I sorta upset the police and MVD, so they sorta took my license away for 6... Word of Advice: Pay your tickets always cuz if you ***** up one you could be in for a long hard road of bussin and bikin /emoticons/[email protected] 2x" width="20" height="20" /> So in the meantime it never got to highway speeds and just teased me in my drive way. Just over the summer I got my license back for my birthday! 6 years in the making. During this time I've done a lot of work on my girl and it wasn't until afterwards I finally got to hit the highway for some off roading fun when my above mentioned problem showed its face. With this being said, I'm a good mechanic but I'm giving it a possibility I may have screwed something up, since it wouldn't be the first time, but the majority of the time I get the job done right the first time cuz I'm just like that ;p

The fixes that have been done in the years I've owned my truck that could be related:

Valve Cover gaskets - There are no oil leaks and oil pressure/response is perfect as said the engine runs great although I can't remember if I torqued the plenum to spec, but I did on the valve covers... Gaskets are the blue rubber Fel-Pros w/ steel skeleton.

EGR valve - Wrenched on good but not the the point the tube should have broke. It was wrenched tightly when I removed it so it didn't require enough effort to snap the tube then either plus I made sure to grip the tube while unbolting it. When I did the valve covers, I did move the EGR tube and I did not make sure to bolt it to the manifold really tightly, but it is pretty snug. I didn't want to risk breaking it because when moving it around, I did slightly bend it, but it did not crack from what I can see and I checked it over pretty good.

Transmission fluid: drained and replaced several times over the past 4 months, but only replaced the filter once since it seems to be a part everybody has to order. Filter came from Checker. I did have the transmission fluid about 1/3 over for awhile, and at the time I first had my above problem. After that the first thing I did was remove the fluid but the problem still exists.

Transfer case fluid: It was black when it came out, and the person who last changed it, used the same plug that they tore up and stripped out. It's one of them inset square ones but it was round in this case. Had to drill this one out and use a tap to get it out. but its all good now and works great!

Fuel evap system: Replaced all hoses, vapor valve & seal, fuel neck, gas cap, & fuel pump o-ring. Did all multiple times since I kept failing the fuel pressure test for emissions, when I found out it was the damn o-ring. There was a bit of dirt under the ring so it held a bit of pressure but not enough to pass since it would give. I cut a hole in the bed above the fuel pump and made a hatch w/ latch so I can get to it without dropping the gas tank since I had to do it about 8 times. It's all sealed and latches tightly /emoticons/[email protected] 2x" width="20" height="20" />

Fuel Pump: Did this one several years ago and got the pump from Rock Auto. The wire looks like its now gashed near the top so I'm replacing the whole thing w/ one from Napa or Motorcraft.

Front Axle rebulid: Had the POS 3 Month year 87 so I had the bad ****** hubs so one was broken and someone stole the plastic lock cap on the one that was broken. Because of water/mud/dirt buildup in the opening, I ended up smoking the bearings after getting my truck back up and running. I went w/ the Bronco Graveyard's knucle out conversion, and installed this. Everything was torqued to spec and the front wheels lock and roll great plus I got 4x4 back, **** YEAH!!!! This was very exciting actually until I went to go play and encountered my problem /emoticons/[email protected] 2x" width="20" height="20" />

Speedometer cable: changed it out, worked for awhile, and now no go. I think the gauge might be stripped from the cable being bad for so long. I'll get to replacing that someday but the tach works great /emoticons/[email protected] 2x" width="20" height="20" />

Now for the abuse I have done to my girl that is related ( I was 19 when I got her so I wasn't the greatest person at first)

One night I was at a stop light and a guy wanted to race so he revved his engine.... I put her in park and revved the engine and let her roar... then dropped it in reverse while it was revved and my foot on the brake like an idiot.... :|

I was a poor kid at the time and couldn't afford to replace my baby's tires, so I went to Big O at night, jumped the wall, and took 4 used, matching tires out of their recycling rack. Well behind the Big O is a huge acre of dirt, which ended up being very soft powder. Well, I'm stealing tires to replace my bald tires, and my truck is in this soft, deep, powder.... She got stuck and because I didn't have the 4x4 cuz of the hubs, I tried rocking my truck to get out which failed... I smelt the clutch burning so I stopped and then we dug a channel for her to crawl out, added a couple of sticks we had to go very far to get, and finally got out. Yeah I know stupid but funny childhood story ya know /emoticons/[email protected] 2x" width="20" height="20" />

For awhile apparantly I left the transfer case in 4high with the wheels not engaged.... More like 4 months.... I drove around quite a bit too cuz gas was cheaper then, and I was on the freeway drivin pretty damn fast a lot hence the black transfer case fluid....

My girl:

87 Ford Bronco Eddie Bauer

302 5.0 EFI pulled from 88 Mustang LX & rebuilt

AOD w/ Cooler pulled from same Mustang & rebuilt

Factory Tow Package

Borg Warner 13-56 Transfer case w/ custom Dremelled 8 Ball shift ****

31in standard Firestone tires

Custom rear trim as amp mount

Custom speaker subwoofer boxes bolted to the body set up for cross fire

Pioneer Premier deck w/ Apple certified iPod control

MB Quart front mid/tweeters w/ cross over box

Rockford Fosgate 12in subwoofer will be reduced to two 10s

Factory center console modded to a cooler by adding drain hole & completely sealing bolt holes

So if anyone has any ideas, I'd love to hear em cuz I don't want to buy a new transmission, but I'm leaning towards it if I can't figure out what it is, and that's hoping it's the problem....

 

[Broncobill78]

Oh My God.

I didn't think it would happen but now there's someone who generates even LONGER posts than mine. WOW man, Thanks. Really, Bull$hit aside. Thank You.

Now, having gotten my gratitude out of the way, it sounds to me like a tranny problem.

Your engine isn't displaying any problems, just the "driveability" part which is pretty much in the transmission. It's an 87' which makes it now 20 freaking years old & unless you or someone else has rebuilt that ancient AOD would make it my prime suspect. Now of course I'm biased having an 88' in the driveway that been nothing more than a damn lawn orniment for the past few weeks because of a $hitty AOD (but I'm gonna fix that with the new AOD sitting on my tranny jack, Really, I am). Since you're a new guy with a truck just like mine I'm not going to mention that I really *don"t* need to know what kind of stereo & subwooferes you have because ****, believe it or not I used to be the same way (but then I had kids & the weight of the world descended upon my shoulders, crushing my will & taking the fun out of everything, but hey, why spoil the surprise). So ANYWAYS, you maybe don't need a *whole* new tranny but it's certainly the place I'd start looking & I'd be prepared to hear that it's old & needs to be rebuilt. You might get a few more years from a junkyard tranny but in the end it'll come to the same thing, you'll need to put something rebuilt & reliable in there.

 

[Seabronc]

Welcome to the Zone > Geez Bill, I think you have found your match /emoticons/[email protected] 2x" width="20" height="20" />

Good luck,

>-

 

[entity-unknown]

I've been leaning towards the tranny too. The AOD was rebuilt when it was put in 8 years ago, and the engine was too. I just beat the tranny up a bit when I first got the truck, cuz I had to show off my girl, which I can bet you did when you were 19 too. If not then what possessed you to buy a Bronco in the first place /emoticons/[email protected] 2x" width="20" height="20" /> I'm probably just gonna buy a whole new one since my girl is worth it. I really appreciate the quick response. I've been reading these forums for about 6 months now and have gotten so much information from this place and your guys posts. It's helped me significantly with my truck so I owe a lot of gratitude to you all.

As for the stereo, it's not a show off thing, its just setup incredibly well and sounds superb because of the choice selection of components. Doesn't rock the block just enough so you can take in every frequency and appreciate the music to its fullest potential. I still even like having it off just to listen to the engine as I cruise along. The Bronco also offers one of the best sound cabins for overall sound development as far as I'm concerned. That's why I posted that part, the rest of the truck is really the prize, sorta like freckles on a girls lips, just a **** feature /emoticons/[email protected] 2x" width="20" height="20" />

Last thing I guess I wanna ask is an opinion. I have a friend that can get me a nice AOD from Jegs for cost, and I like the Dominator Jr. I found at http://www.transmissioncenter.net/aod.htm.

There's a huge price difference but I'm not too concerned, I just want a good one for decent 4x4 and one that will last, even though I don't beat her up anymore. I just need to get to anywhere I want so I can go explore and hunt. Dead deer sections inside the cabin while driving home waiting to cook em up.... MMMMM. So with your experience and knowledge who would you say I should go with? And I'm glad I could earn your respect on my detail and story telling /emoticons/[email protected] 2x" width="20" height="20" />

 

[4X4RedNeck]

I've been leaning towards the tranny too. The AOD was rebuilt when it was put in 8 years ago, and the engine was too. I just beat the tranny up a bit when I first got the truck, cuz I had to show off my girl, which I can bet you did when you were 19 too. If not then what possessed you to buy a Bronco in the first place /emoticons/[email protected] 2x" width="20" height="20" /> I'm probably just gonna buy a whole new one since my girl is worth it. I really appreciate the quick response. I've been reading these forums for about 6 months now and have gotten so much information from this place and your guys posts. It's helped me significantly with my truck so I owe a lot of gratitude to you all.
As for the stereo, it's not a show off thing, its just setup incredibly well and sounds superb because of the choice selection of components. Doesn't rock the block just enough so you can take in every frequency and appreciate the music to its fullest potential. I still even like having it off just to listen to the engine as I cruise along. The Bronco also offers one of the best sound cabins for overall sound development as far as I'm concerned. That's why I posted that part, the rest of the truck is really the prize, sorta like freckles on a girls lips, just a **** feature /emoticons/[email protected] 2x" width="20" height="20" />

Last thing I guess I wanna ask is an opinion. I have a friend that can get me a nice AOD from Jegs for cost, and I like the Dominator Jr. I found at http://www.transmissioncenter.net/aod.htm.

There's a huge price difference but I'm not too concerned, I just want a good one for decent 4x4 and one that will last, even though I don't beat her up anymore. I just need to get to anywhere I want so I can go explore and hunt. Dead deer sections inside the cabin while driving home waiting to cook em up.... MMMMM. So with your experience and knowledge who would you say I should go with? And I'm glad I could earn your respect on my detail and story telling /emoticons/[email protected] 2x" width="20" height="20" />

Quiet frankly I would check your engine before you check your tranny. Valves and pistons more importantly. Valves can wear and ruin a piston (break piston heads or crack them, or even crack heads giving you bad compression), backfiring and not giving you the power you need.

 

[entity-unknown]

Well that breaks to a level of the engine I have only seen from over shoulders or in pictures and something I would not know how to check. When I did the valve covers, the lifters were fine, but that's not what you're talking about here. Suggestion or are you just straight saying, pull the engine apart and physically look at the pistons and valves? Also, would an engine running too cold at high compression for long time? And do you still feel it's the engine even when I put it in Neutral or Park and it revs just fine, but if I take off while not letting it sit it will still have no acceleration until I turn it off and wait for awhile? I understand there is a difference in load when in gear vs in neutral/park, but it has this problem from 400 - 2100 RPM's once it craps out, 2100 being my limit because I can not break that rev limit when it's not working right, but I can still rev it to 3+ grand in neutral/park and it sounds great no backfire. I haven't stopped thinkin bout the engine as a possibility but for the issue, it just seems to lean towards the tranny.

 

[Justshootme84]

My first impression is that your overdrive (OD) is on it's way out. Have you tried any additives like Lucas or other brands? they're usually too late to do any good if your clutch bands are worn out and slipping. Best advice i can give is take the Bronco to at least 3 transmission shops and have them try to diagnose your problem. Two shops will likely want to completely overhaul or replace the AOD, while the third shop should be able to tell you without a doubt if it's just a vacuum leak on the motor or something similar. It is possible that an engine problem can mislead you into believing the tranny is at fault, too. You can have a compression test done, check the timing, tune-up the motor, etc. Strange things happen to a vehicle when it sits for along time without being driven. Mice make nests inside the air cleaner, mud daubers build nests right on top of linkages or cables, rubber seals dry out and fluids go bad from condensation/ moisture. JSM84

 

[4X4RedNeck]

My first impression is that your overdrive (OD) is on it's way out. Have you tried any additives like Lucas or other brands? they're usually too late to do any good if your clutch bands are worn out and slipping. Best advice i can give is take the Bronco to at least 3 transmission shops and have them try to diagnose your problem. Two shops will likely want to completely overhaul or replace the AOD, while the third shop should be able to tell you without a doubt if it's just a vacuum leak on the motor or something similar. It is possible that an engine problem can mislead you into believing the tranny is at fault, too. You can have a compression test done, check the timing, tune-up the motor, etc. Strange things happen to a vehicle when it sits for along time without being driven. Mice make nests inside the air cleaner, mud daubers build nests right on top of linkages or cables, rubber seals dry out and fluids go bad from condensation/ moisture. JSM84

I agree. Take it in, see what a tranny shop has to say. But a compression check, spark plug check, etc. could be one of the things you do as well.

 

[Broncobill78]

Welcome to the Zone > Geez Bill, I think you have found your match /emoticons/[email protected] 2x" width="20" height="20" />
Good luck,

>-

Damn Fred, I was hoping nobody would notice my admission, much less call me on it <grin>. Some days you just can't win /emoticons/[email protected] 2x" width="20" height="20" />

 

[entity-unknown]

Cool deal. Well Timing was done the other day, but I got some more work to do on her (as always) I totally appreciate the advice and I'll post how it turns out cuz I'll be damned but I'm gonna fix this one and I'm sure someone will benefit from the results. On another note, you all totally rock for the fast, and great responses!

 

[entity-unknown]

Problem fixed! Replaced the transmission and rear axle (which needed to be replaced anyways cuz of other problems) and the problem was still there. After taking an influenced relaxing break the other evening, I thought about it.... Considering the way metal heats and cools and the way it's acting it's gotta be a sensor..... So I replaced the O2 sensor and cleaned the MAF and what do ya know? I got a bad ass Beast back on the road that runs better than ever! Hope this helps someone out.

 

[johnnyreb]

I have a very odd issue. My truck runs great almost all the time. My main issue is when I'm driving on the highway in 4th gear at or over 2200 RPM's for about 15 to 20 minutes, my truck sort of jerks a bit and then starts to slow down. I can hold about 2000 - 2100 RPMs in any gear but I have no acceleration. If I try to accelerate it will make a sound like a backfire or clanking. I've only tried to accelerate hard twice so I couldn't totally place the sound since I didn't want to make it any worse. When I have to stop, then go again, there is still no power/acceleration through any gear and it takes me about 1 minute to get up to regular posted speeds. If I shut the truck off for about 15 minutes, I can drive perfectly forever, unless I go back up to 4th gear above 2000 RPM, then I'm back to the issue. If I let it sit for about 30 minutes, I can go the full 15 - 20 minutes again. During this time I can also go in Neutral or Park (No I didn't try on the highway only while stopped) I can rev the engine and it responds perfectly. To me it seems like losing pressure in the transmission, being starved of fuel, or a seal giving, but definitely revolves around heavy load or high pressure for a prlonged period of time. Should be simple huh? :|

I also have a slightly hard shift into 4th gear if I'm at a medium or slow acceleration. Mild and hard accelerations almost always give a smooth shift. 2nd gear also has a pretty rough shift typically and sometimes has exhibits almost the same lack of power, as well the backfire/clank sound. There is also a rare rough shift into reverse and sometimes drive. Drive is pretty smooth now after adjusting the TVC so I'm gonna probably gonna try adjusting this again. There's also a clunk when the shifting into drive or reverse as well but I'm sure that one is u-joints so I'm gettin to those this weekend as well. The truck shudders at speeds over 2200 RPMs as well.

The truck sat for about 3 years, cuz I sorta upset the police and MVD, so they sorta took my license away for 6... Word of Advice: Pay your tickets always cuz if you ***** up one you could be in for a long hard road of bussin and bikin /emoticons/[email protected] 2x" width="20" height="20" /> So in the meantime it never got to highway speeds and just teased me in my drive way. Just over the summer I got my license back for my birthday! 6 years in the making. During this time I've done a lot of work on my girl and it wasn't until afterwards I finally got to hit the highway for some off roading fun when my above mentioned problem showed its face. With this being said, I'm a good mechanic but I'm giving it a possibility I may have ******* something up, since it wouldn't be the first time, but the majority of the time I get the job done right the first time cuz I'm just like that ;p

The fixes that have been done in the years I've owned my truck that could be related:

Valve Cover gaskets - There are no oil leaks and oil pressure/response is perfect as said the engine runs great although I can't remember if I torqued the plenum to spec, but I did on the valve covers... Gaskets are the blue rubber Fel-Pros w/ steel skeleton.

EGR valve - Wrenched on good but not the the point the tube should have broke. It was wrenched tightly when I removed it so it didn't require enough effort to snap the tube then either plus I made sure to grip the tube while unbolting it. When I did the valve covers, I did move the EGR tube and I did not make sure to bolt it to the manifold really tightly, but it is pretty snug. I didn't want to risk breaking it because when moving it around, I did slightly bend it, but it did not crack from what I can see and I checked it over pretty good.

Transmission fluid: drained and replaced several times over the past 4 months, but only replaced the filter once since it seems to be a part everybody has to order. Filter came from Checker. I did have the transmission fluid about 1/3 over for awhile, and at the time I first had my above problem. After that the first thing I did was remove the fluid but the problem still exists.

Transfer case fluid: It was black when it came out, and the person who last changed it, used the same plug that they tore up and stripped out. It's one of them inset square ones but it was round in this case. Had to drill this one out and use a tap to get it out. but its all good now and works great!

Fuel evap system: Replaced all hoses, vapor valve & seal, fuel neck, gas cap, & fuel pump o-ring. Did all multiple times since I kept failing the fuel pressure test for emissions, when I found out it was the damn o-ring. There was a bit of dirt under the ring so it held a bit of pressure but not enough to pass since it would give. I cut a hole in the bed above the fuel pump and made a hatch w/ latch so I can get to it without dropping the gas tank since I had to do it about 8 times. It's all sealed and latches tightly /emoticons/[email protected] 2x" width="20" height="20" />

Fuel Pump: Did this one several years ago and got the pump from Rock Auto. The wire looks like its now gashed near the top so I'm replacing the whole thing w/ one from Napa or Motorcraft.

Front Axle rebulid: Had the POS 3 Month year 87 so I had the bad ****** hubs so one was broken and someone stole the plastic lock cap on the one that was broken. Because of water/mud/dirt buildup in the opening, I ended up smoking the bearings after getting my truck back up and running. I went w/ the Bronco Graveyard's knucle out conversion, and installed this. Everything was torqued to spec and the front wheels lock and roll great plus I got 4x4 back, **** YEAH!!!! This was very exciting actually until I went to go play and encountered my problem /emoticons/[email protected] 2x" width="20" height="20" />

Speedometer cable: changed it out, worked for awhile, and now no go. I think the gauge might be stripped from the cable being bad for so long. I'll get to replacing that someday but the tach works great /emoticons/[email protected] 2x" width="20" height="20" />

Now for the abuse I have done to my girl that is related ( I was 19 when I got her so I wasn't the greatest person at first)

One night I was at a stop light and a guy wanted to race so he revved his engine.... I put her in park and revved the engine and let her roar... then dropped it in reverse while it was revved and my foot on the brake like an idiot.... :|

I was a poor kid at the time and couldn't afford to replace my baby's tires, so I went to Big O at night, jumped the wall, and took 4 used, matching tires out of their recycling rack. Well behind the Big O is a huge acre of dirt, which ended up being very soft powder. Well, I'm stealing tires to replace my bald tires, and my truck is in this soft, deep, powder.... She got stuck and because I didn't have the 4x4 cuz of the hubs, I tried rocking my truck to get out which failed... I smelt the clutch burning so I stopped and then we dug a channel for her to crawl out, added a couple of sticks we had to go very far to get, and finally got out. Yeah I know stupid but funny childhood story ya know /emoticons/[email protected] 2x" width="20" height="20" />

For awhile apparantly I left the transfer case in 4high with the wheels not engaged.... More like 4 months.... I drove around quite a bit too cuz gas was cheaper then, and I was on the freeway drivin pretty damn fast a lot hence the black transfer case fluid....

My girl:

87 Ford Bronco Eddie Bauer

302 5.0 EFI pulled from 88 Mustang LX & rebuilt

AOD w/ Cooler pulled from same Mustang & rebuilt

Factory Tow Package

Borg Warner 13-56 Transfer case w/ custom Dremelled 8 Ball shift ****

31in standard Firestone tires

Custom rear trim as amp mount

Custom speaker subwoofer boxes bolted to the body set up for cross fire

Pioneer Premier deck w/ Apple certified iPod control

MB Quart front mid/tweeters w/ cross over box

Rockford Fosgate 12in subwoofer will be reduced to two 10s

Factory center console modded to a cooler by adding drain hole & completely sealing bolt holes

So if anyone has any ideas, I'd love to hear em cuz I don't want to buy a new transmission, but I'm leaning towards it if I can't figure out what it is, and that's hoping it's the problem....

Ethanol gas? If so my guess would be to start the complete fuel system. From the tank to the carb or fuel injection. Ethanol gas starts changing to a tar like sunstance in about a week or 2. Put some in a clear bottle and check it (from the tank) as soon as you pour it in. Notice the bottom will get a dark like tar.Put a cap on it and shake it and you,ll see disturbing stuff. I went through that and its costly and alot of work. Good luck.