86 Still driving me nuts

[popeye46]

I am still having problems with my 86 Bronco II 160,000 miles, after warming up it wants to bog down and start to sputter and kick like it is running out of gas.....if I floor it it will downshift (automatic) and run good again until it reaches cruising speed again...and then do it all over again......funny thing was that it used to be that if I were to stop at a stop sign or light and sit for a minute it would take off and be just fine for the rest of the trip.....if I stopped and turned it off it would go back to the usual kicking and sputtering again... I have read other tips and hints and have done the following......disconnected the O2 sensor......no effect at all did not run better or worst did same thing......checked and replace most of the vacuum hoses.....found a little trans fluid in the hose at the vacuum modulator on the trans so I replaced that also....Test drive and now it runs worse and will die....starts right back up but continues to do the same thing......replaced the ignition module.......also installed a new thermostat as it seemed to be taking a long time to warm up on cold mornings.......test drive and the same ole thing happens......going to replace the throttle position sensor and see if that helps......have also been told that the temp sensor could be causing my problems......would greatly appreciate any help as this is now driving me crazy.....and don't want to pay for a mechanics new car for him to solve this......Like this little car and don't really want to get rid of it. But also don't want to spend a fortune on the 2.9......4.0 swap in the distant future so that I can give this one to my grandson.......thanx for any help and have a nice day.........Mike

 

[Runnin'OnEmpty]

Mike, sounds like you've already replaced the easy stuff. /emoticons/[email protected] 2x" width="20" height="20" />

It sounds like a fuel delivery problem to me. I'd change the fuel filter first, simply because it's easy and cheap. If the trouble persists, then suspect a bad fuel pump. Unfortunately your model might have two, one in the tank and another in the line.

Does an 86 have a MAF sensor? If so, then that would also cause the problems you describe.....

 

[mauser1111]

Does that year have both a MAP sensor and a Idle Aur control valve if so you can at least take off the Idle air control valve and clean it. The map sensor would have to be tested, Also it sounds like an EGR valve, if it starts doing it after it warms up. Thats th reason I cant see it being fuel related, if it runs fine at first and then acts up after youve got it warmed up it wouldnt be a fuel pump because they have to be working at all time right at start up and then from then on.

 

[BroncoJoe19]

I am still having problems with my 86 Bronco II 160,000 miles, after warming up it wants to bog down and start to sputter and kick like it is running out of gas.....if I floor it it will downshift (automatic) and run good again until it reaches cruising speed again...and then do it all over again......funny thing was that it used to be that if I were to stop at a stop sign or light and sit for a minute it would take off and be just fine for the rest of the trip.....if I stopped and turned it off it would go back to the usual kicking and sputtering again... <SNIP>.........Mike

I wouldn't think that it is your throttle position sensor.

I just replaced the MAP sensor on my Bronco it cost me $100. That could be your problem, but what I found was my problem, is that my air filter was extreemly filthy. I suspect that there was so little air getting through it, that the MAP sensor could no longer compensate for it.

If you haven't done it in a while consider giving you car a good tuneup. Plugs, cap, rotor, air and fuel filters.

Hope this helps.

Good luck

joe

 

[89 Deuce Boy]

I just went through the exact same thing and did all the swaps that you said plus more and it ended being that the sock or (filter) on the fuel pump itself got old and eroded and rust and grime was getting in the fuel pump which sucks to change but that is what im sure is wrong with yours too.

 

[Jersey]

3 easy ways to test the map sensor: 1 make sure it is getting a good constant vacuum. you can get a cheap hand held vacuum pump at most auto parts stores. 2 hook a vacuum line to the map sensor from the vac. pump. Make sure it holds at least 12" of vac. 3 unplug the mapsensor, then try driving it. The older eec-IV systems will usually use a default value in its place, and if the condition pretty much goes away, thats your problem. Good Luck!

 

[broncodanger]

i had a simaller problem with my 89 bronco II $500 in mechanics i ended up dropping the tank and changing the pump fuel pump and runs fine now. pump cost $180.

 

[FordBroncoII]

Looks like you have put a lot of work into the vehicle!

My only comments which may not relate to or solve the problem are:

A) I experienced this problem twice since owning my own Ford Bronco II 1987 4WD

a) The first time was when I had the manual transmission replaced and the vehicle sat in the shop for a few weeks

Putting in a new gas filter and new gasoline helped, but did not solve the problem completely.

I found the hose connections loose at the vacuum pump and tightened these hose connections and sealed them.

This did solve the problem;

B) The second time was when I found an exhaust leak around the gas oxygen sensor; Once this was repaired, the problem was also corrected;

 

[viperfangs2]

O man bronco 2s and ford rangers are well know for being a vacuum nightmare double and triple check the vacuum lines or hoses what ever you want to call them trust me it will save you lots of money!!!!