Hey guys my 96 F250 has been running rough for over a year and its finally time to try to fix her or move on


Here's my original post:
https://www.ford-trucks.com/forums/1...f250-351w.html


Basically the truck will start up fast and right after will idle well and you can snap the throttle up to 60-70% and it sounds great, but after 2-3 minutes its missing at idle and it bogs and stumbles hard on acceleration. I've checked and changed so many things.


I checked my PCM and of course 2 of the capacitors were leaking badly so I replaced them and no change. There was quite a bit of damage to the Board on the PCM so I ordered a refurb from Rockauto because they have an awesome return policy. The refurb did not fix my problem either, so I returned it and only lost 4.50$ in shipping.


Here's the best part. After all this I say screw it and call the local ford dealership in mesa. I make and appointment with them at 7am the next day. I get there and actually show the guy my truck and what is happening he takes all kinds of notes and I tell them max 2hrs of diagnostic time. They call me an hour and a half later and tell me my truck is too old for them to work on. Idiots!


I've found something though that might be really telling. When I run my KOER test with the OBD-1 tester after I get the 111 and the test is done, if I don't unplug the tester the engine runs GREAT. Revs up fast and quick and idles well. As soon as I unplug or turn the tester off it starts missing and stumbling.


Does the tester put the computer in open loop? Could this mean its a sensor causing my problems?


Thanks everybody

 

no codes in both KOEO and KOER, your fuel pressure seems good as per your other thread, correct?




do you have any u pick u pull junk yards around your area? you can get a lot of parts that you can use for diagnostics and replacements. its also nice to confirm all of your spare parts are good once you have a good running truck. in other words, once you get it working replace one thing at a time, coil, see if it runs good. eec, see if it runs good...and so on.

 

Yea no codes I just ran it today. Fuel pressure is at 30-32 on both tanks. I just tried a new MAP sensor and a oxygen sensor too and nothing.


Luckily the weather in AZ has been phenomenal so I have been able to ride my motorcycle but it can still get cold!

 

What does the fuel pressure look like both when it starts up and when it starts running like crap?

 

tagged so I can follow along

 

Following as well..