Possible PCM issue?

[gold10go4]

Have a '93 explorer. It usually runs good when cold, but as it heats up it starts to run rough. I have to give it gas at the stoplight to keep it from shutting down.

The general maintenance items have been changed - plugs, wires, fuel filter, etc. I couldn't find any obvious problems - vacuum hoses, etc.

Finally took it to a local repair facility, but the thing wouldn't act up when it was there (go figure). The mechanic said it wasn't listing any trouble codes, and he suspected it might be the PCM. I think this was simply a best-guess thing on his part. I didn't want to invest $600 in a guess. I can get a new one for less than $150, but I'm wondering if the PCM seems like the most likely culprit.

[shorod]

I'd be more inclined to investigate the fuel pump and Idle Air Control servo before jumping to the PCM.

Fuel pumps are DC motors, they can fail as they heat up. Also, the fuel pump uses fuel to keep it cool. Does the rough running seem worse when the fuel level is lower? What is the fuel pressure at the fuel rail when it is running rough?

Does the engine try to stall if you turn the steering wheel all the way to lock in one direction and hold it there for 1 or 2 seconds? Don't hold it at lock for more than a few seconds as that's quite hard on the pump.

-Rod

[way2old]

I have to agree with Rod. Ford PCM's are not prone to failure. It is possible, but not likely the first thing to go after. You might also check your coolant temperature and air intake temperature sensors to be sure they are working properly. Maybe even the EGR system. Since it seems to be heat related, I would check these sensors and also connections and wiring for corrosion.