I have a 94 7.5l f-250 that is started giving problems. You can drive a day or two and it gives no trouble then out of nowhere you will crank it and it acts like it is running to rich and smokes and throws a fit like it is getting too much fuel. Then you leave it day or so and then it will run correctly with no problems... I self checked the codes a week ago after this issue and was getting mostly low voltage problems at all the sensors. I checked the alternator and thought that I had a bad voltage regulator. I replaced the alternator cleared codes and immediately the problem went away. I used it on the farm all week and had no issues. Little did I know that this morning here we would go again. I self checked codes today and I'm getting low voltage codes/ not grounded at the sensors again as well as now I'm getting a couple solenoid codes. I noticed that from the alternator wiring does go to the solenoid. How would the solenoid have any thing to do with what voltage is sent to the computer/sensors? I thought map sensor or throttle position sensor. Or possibly an oxygen sensor that is telling the truck it needs more fuel. But it still doesn't explain that with letting it sit for a while that it will crank and work just fine with no check engine or issues? If anyone has dealt with anything like this please help. This is nuts!!

 

What codes were you getting? Do you still have a check engine light on?

It kind of reminds me of a bad engine coolant temperature sensor that I had...would start fine when cold but acted like it was flooded when warm. It wasn't bad enough to throw a code, but the sensor failed when testing it.

 

If the sensors are showing fault for misleading voltage, I'd be inclined to pull the PCM and the board a look over.

Failing capacitors could be the culprit.