1988 F350
7.5 Liter 460 EFI
Gas / Auto


Here's the backstory-

Bought the truck used recently and took it on a couple hour drive making stops along the way from 5 minutes to 30 minutes and had no problems till I parked it for about 15 minutes and tried to start it. No response. Tried jumping it, didnt work. Had the starter tested and it was good. Battery didnt test so good so I replaced it. Only problem is, I replaced it backwards somehow and fried some of the electronics. I took it to a shop and they diagnosed that I fried the ECM, Fuel Relay and Computer (I thought the ECM and Computer were the same??) and also some previous wiring issues (mostly ground issues) inherited from the previous owner. So they replaced/repaired those three items. Now the truck runs like crap especially when going up hills, slowing almost to a stop. If I mash on the gas, the RPM's respond but the truck is struggling significantly. It idles just fine and seems not as bad on flat ground but throttle response is extremely sluggish and is no where near what it was before this electrical mishap. Oh, and now all of the sudden I seem to have a exhaust leak...
I replaced the large canister fuel filter (is there another one?) and air filter which showed no improvement. Also am only using premium fuel and just for kicks, added some fuel system/injector cleaner.
I have not run codes yet, but plan on getting a code reader this Friday. I know I could do it with a paper clip, but would rather just get a code reader.

I appreciate any help that you may have!

 

There are several sensors that control things you are talking about. Do you have a manual (Haynes or other) to go through the test procedures? That is where I would start. Get a multimeter and vacuum tester and start going after all sensors to make sure they check out. Could be a number of things.

One simple thing to check is make sure the vacuum lines are OK. They often get rotten and a little work in the engine bay makes them fail. Or like me they get melted and stop sending vacuum where it was supposed to go...

The PCM (Powertrain Control Module) is the "computer" for the truck. This is the EEC-IV computer.

Working through some issues on my 1986 and I can tell you there is no "silver bullet". Have to go test and check everything...

One thing I would not do is start throwing parts at it. That will get expensive and frustrate you quickly.

 

Thanks cbrown, gonna get myself a manual and start with checking those vacuum lines