My 93 F150 has a 5.8L V8 in it with the E4OD tranny. It has had some exhaust issues due to plugged cats but other than that it has alwys run great. I gutted the front cat and cut out the back one a month or so ago. 2 weeks ago I was driving along and the engine stumbled and the chek engine light flashed but it straightened right up and kept going. It started doing this more and more until the check engine light would come on for a while and the engine would run rough and have trouble accelerating
I used a test light and a jumper and pulled a handful of codes that were all over the place. I cleared the computer and tryed it again. Then the CEL would come on and the tranny felt as if it was stuck in 3rd gear and the engine would run rough. I took it to Advance Auto by starting out in 1st and running up through the gears manually. Half way there the engine threw out a cloud of black smoke(rich) and ran smooth and the tranny shifted normal although the CEL stayed on. Advance Auto couldn't help me so I tried to get more codes when I got home. I couldn't pull them but the CEL cleared and for the next three days the truck ran fine . Yesterday it was a no start and when I jumper the OBD connecter I get no codes or reaction except the fuel pump selected comes on and stays on. IMO the PCM is fried, the truck has lost it's mind. Any other opinions?
Kenny

 

I think you are saying that the selected fuel pump comes on all the time the key is in the on position.
If this is so yes it sounds like your PCM Computer is bad.

 

That is correct. I had a similar problem with a 93 Geo Storm and when the computer started to die the car ran crazy and kicked out all manner of codes. Just like this one.

Will a junk yard PCM from a similar truck work?
Kenny

 

yea just make sure its the same motor and tranny and the codes are the same.

 

I'd suggest double checking the ground for the ECU harness, but it does sound like an ECU issue.

 

OK I bought a reman ECU from autocomputerexchange.com on-line. $250 plus tax and shipping with a 1 year warranty. I ordered it on Monday got it yesterday and installed it this morning. The truck fired right up and runs like a top with no CEL. I have used this company before and gotten good results.

Kenny