transmission or something with throttle

ok. i have a 1990 bronco 4x4 5.0 302 V8 automatic. i seem to always have problems with it, whether it won't crank or now i seem to have something wrong with maybe the transmission. i have 33s so my speedometer is off by about 5 or 6 mph. and when i'm going 45-55 and i barely hit the gas my RPMs will jump to bout 2500 or 3000 from about 1500 when i can get it to keep a steady speed. it's like it's always goin into the passing gear and i ain't wantin it to or if i'm goin up a hill it will hard shift into 3rd from 4th. if anybody knows what kinda problem and how to fix it please tell me. thanks!

what gears do you have in your axle, with 33' you usually need 3.73 or 4.11 gears for your engine to move them like your old stock tires.

I'm no Trans expert, but it sounds like it's dropping out of OD because of engine load. Check the forum for a post on tire size and gear ratio. You may have to change gearing or go to smaller diameter tires.

yo,

Is it an E4OD w/OD on-off switch located on dash to right of steering column?

Such as this in a 90



Source: by My90Bronco?

First try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19

http://broncozone.com/topic/14269-code-reader/page__pid__74587__mode__threaded

The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.

Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.

Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.

Do Key On Engine Off (KOEO) portion first.

Look Codes up in my broncolinks.com site using the new Search function.

And Post em here according to:

KOEO

&

KOER

========

Vacuum Leak Test; On an idling engine check for vacuum leaks using a ~3' garden hose section.

On COLD ENGINE only, use propane torch w/rubber hose attached, UNLIT or spray carb cleaner, when it gets to the the leak the RPMs will rise.

Also check:

vacuum hoses; intake manifold gasket & throttle body; & Line to & the power brake booster, PCV line

vacuum reservoirs:

EGR Sys Vacuum Tank & 2ndry air (looks like a coffee can in earlier years);

Thermactor Air Bypass Solenoid (TAB, AIRB, AM1) w/Pink vacuum line & Air Bypass Valve (AIR BPV) & Thermactor Air Diverter Solenoid (TAD, AIRD, AM2) w/Yellow vacuum line & Air Diverter Valve or Air Control Valve (ACV) see my site @ http://www.broncolinks.com/index.php?index=416 & EGR Vacuum Regulator (EVR); also called EGR Vacuum Solenoid & EGR Valve Position (EVP) - MIESK5 NOTE: EVP is used on all years except for 95 5.8L California models & all 96, they use the DPFE Sensor instead of EGR Valve Position Sensor (EVP) etc, see my site @ http://www.broncolinks.com/index.php?index=146.

AC, heater, defroster, vent control ckt & vacuum tank (plastic ball type), under dash & lines to heat/blend/etc. doors; power brake booster, & HVAC vacuum reservoir

Carbon Canister (Charcoal Canister, Vapor Canister, Evaporative Emission (EVAP) Canister for the Evaporative System

======

Could be an ignition issue too (PIP inside distributor) as in;

Shudders, Bogs, & Intermittent No-Spark: Spark w/SPOUT Connector Un-Plugged, but No-Spark w/SPOUT Connected, due to distributor, in a 93 & KOER test won't begin; "...The engine starts to bogg down and then it shudders before it downshifts and smooths out. (example, when rpm’s drop going up an incline it will shudder for a few seconds before the rpm’s increase and it drops out of OD). If I remove the SPOUT the shuddering downshift problems goes away; then, when I replace the SPOUT the shuddering downshift problems comes back; Distributor was causing the problem..."

Source: by buck45 at Ford Bronco Zone Forums http://broncozone.com/forums/index.php?showtopic=18748

Shudders, Bogs, etc. & Intermittent No-Spark: Spark w/SPOUT Connector Un-Plugged, but Falter and/or No-Spark w/SPOUT Connected (similar to Hesitation, Stumble, Stall, Miss, No Start, No Spark); It seems that the insulation around many PIP sensors breaks down prematurely - a condition that leads to shorting of the wires leading to the TFI ignition module. I always replace a PIP sensor along with a defective ignition module, if it has "soft" insulation...";

or

Any Shudder?

; If the shudder occurs a):

during the 3-4 or 4-3 shift at HEAVY throttle,or B) at 40mph in 2, OD OFF, and OD, or c) at the same RPM in every gear,

or d) coasting, cruising, or in R, or e) during extended light braking, then it is NOT TC clutch shudder;

The following is a list of common vehicle concerns that have been misdiagnosed as torque converter clutch shudder. For diagnosis of the following items, refer to the appropriate sections of the workshop manual and the Powertrain Control/Emissions Diagnosis manual (PCED).

Spark plugs - check for cracks, high resistance or broken insulators.

Plug wires.

Fuel injector - filter may be plugged.

Fuel contamination - engine runs poorly.

EGR valve - valve may let in too much exhaust gas and cause engine to run lean.

Vacuum leak - engine will not get correct air/fuel mixture.

MAP sensor - improper air/fuel mixture. HO2S sensor - too rich/lean air/fuel mixture.

Fuel pressure - may be too low.

Engine mounts -loose/damaged mounts can cause vibration concerns.

Axle joints - check for vibration

how do i figure out what gears are in it? and are those expensive to change? preciate the help fellas!

there will be an axle code on the information sticker on your door jam, from that code we can tell you what your stock gears are. the gears themselves arn't very expensive but the work to change them if you DIY is a PITA, but if you find a good axle guy then you end up paying for a couple of hours of labour

iight. thanks man. that helps a lot. i see a lot of recommendations for the 4.56 gears. that's probably what i'll go with. preciate it.

4.56 are pretty short for only running 33's if you lok at the different regearing threads in the how to teck section or pinned in the 80-96 forum you'll find a gearing chart that lays out your options as far as gearing for mileage , or power based on your tire size and engine speed.

i've almost have the same problem as you with stock 3.08 gears with my 31's, my truck would rather cruise at 65 mph in od than 55 and kicks down whenever Im not on flat ground,

with 33's though you more than likely have stock 3.55 gears, and going to a 3.73 or 4.11 would give you alot more power without sacrificing mileage and unless you intend on moving up in tire size soon I would stay away from the 4.56.

remember what ever you change the rear to, you have to do the same to the front but with reverse rotation gears.

yo,

Did you do the self-test for codes?

I assume you have an E4OD;

Possible internal issues could be dirty/damaged CB7 check ball in valve body or plate seat (due to contaminated fluid)

Next; re, "... have 33s so my speedometer is off by about 5 or 6 mph..."

You can correct the speedo by changing the speedometer's gears (at transfer case); "...The speedo gear is retained by a c-clip, visible just under my fingers here..."Steve83 wrote, "...Its magnets & tone ring are all inside that sensor body. The plastic gear drives the sensor's shaft, and that shaft drives the speedo cable. Pull the C-clip off the gear and then pull the gear off the sensor. it makes 6 pulses per rev..."

Source: by Keith L (TTB Blows, Bling-Bling) at http://www.supermotors.net/clubs/superford/registry/139/13464

Gear Color Codes, 80 and up

Source: by JBG via Seabronc (Rosie, Fred W) at http://www.supermotors.net/clubs/superford/registry/media/280161

This is how you can tell how much of a difference different teeth make. If you have a 20 tooth gear. One less tooth gear would decrease your speedometer 5% (1/20), two less teeth 10% (2/20). For one or two more teeth it would increase the speedometer 5% and 10%. This is as close as your going to get based on your actual difference. by John

They are about $3 each at your local Ford dealer

http://www.fordracingparts.com/download/charts/142.pdf