Thanks guys, I will try switching out the PCM

The reason why I gave the example of my old Jeep is because it was a Frankenstein (Grand Wagoneer) with several different Ford, Chrysler, Amc, etc parts, and the PCM was that of a Ford. Also, my dad's 91 F150 had a bad PCM and it behaved in the same way I described my Jeep behaving.

Thanks again for all the info, hopefully this will fix the truck. I'm running out of time on my loaner vehicle!

 

Can anyone tell me where the PCM is?

 

It is in the drivers kick panel in the cab. You remove it from under the hood through the inter fender and fender. It has a 10 mm bolt in the plug you have to back out to get the plug off. Then two small screws.
You may also have to turn or take the drivers front tire off.

The photo below shows where it is.


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Hey, is that truck yours? It's really nice of you to keep demonstrators around for us shade-tree guys! Do you have one to show what the top side of an E4OD looks like?

 

Top side of an E4OD:


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dude, you rock!

 

subford is the photo/diagram king of fte.

 

Thank you SubFord, that was very helpful.

I've since pulled the old one out, and it smells like burnt electronics. Come to think of it, when the truck died, I smelled the same odor- so I'm pretty confident the PCM is the issue here.

I've been trying to find one locally for about 2 hours now and I'm having zero luck. Seems that nobody has one that crosses to the number on my unit.

This is the number:
F3TF-12A650-ZB

I realize I'm probably going to have to order one of these new from a parts house, but at just under $300 a pop, I'd like to find a used unit instead. I can't find one on EBAY or anywhere else online.

If anyone has any suggestions, or by some stroke of crazy luck, has one they'd like to sell, please let me know.

Thanks again.

 

Try searching this number:
F3TF-ZB
Most do list the base number online.

 

So after a tedious search, I could not find a PCM anywhere locally; found a few on the internet for reasonable prices, but they only came with a 30 day warranty.

I ended up buying one from Autozone because it was cheaper than NAPA and both offered a one year warranty. Around $300 and had to order it.

Installed it and the truck runs now! It actually seems to run better than before. One weird thing- the airbag light that used to be on continuously now blinks? Oh well, I'll just have to crush that light bulb

Truck still hesitates from a dead stop like it did before, but I figured the two problems were unrelated anyway.

So-Thanks everyone (subford ), you guys were a real help.

 

I have a 94 4.0 ranger with the simular problems It will cold start just fine and drive but will start missing if left at an idle and has a hard time restarting changed relays and pcm and still have continuous fuel pump with key on any ideas?

 

Sounds like a bad computer.
Here is how it should work. When the ignition is switched to the ON position, it turns the EEC Power Relay on. The EEC Power Relay provides power to the EEC-IV processor and the control side of the fuel pump relay. Power for the fuel pump is supplied through a high current fuse in the engine compartment fuse box. From the high current fuse, current flow is through the fuel pump relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump. The IFS switch is a safety device used to shut off the fuel pump in the event of a collision. If the IFS switch is "tripped," it must be reset by depressing the white or red button on the top of the switch. The fuel pump relay is controlled by the Powertrain Control Module (PCM).

When the ignition switch is turned to the ON position, the fuel pump will operate. If the ignition switch is not turned to the START position, the PCM will shut the fuel pump off after approximately one second. The PCM will operate the fuel pump when the ignition is in the START position to provide fuel while cranking.

After the engine starts, the PCM will continue to operate the fuel pump unless the engine stops, engine speed drops below 120 rpm, or the IFS switch is "tripped."