I have a '94 F150 with a 302, E4OD auto. The problem is that lately since the weather is warming up the CEL comes on and the truck runs rough and shifts up rough or hard. It only does this when the outside temp is around 70 or above. It runs perfect and shifts perfect (no CEL) if the temp is around 65 or below. This doesn't sound like a TPS or O2 sensor to me. I had O'Rielly's check for codes while the CEL was on and there were none. Could it be MAF or EGR? Or maybe something else? Thanks

 

You sure O'Reilly's actually did a proper scan? You don't have OBD-2, you have the old EEC.

 

Yea, they had the correct reader and I assume that they know how to use it. They plugged in under the hood at the firewall so it had to be the right one. Maybe not. I just now drove it and the outside temp is 71 and the CEL comes on and goes off. Any colder and it would simply stay off and any hotter it would simply stay on.

 

There are 3 tests that have to be done - key on engine off, continuous memory, and key on engine running.

 

Thank you, but last night I removed the IAT sensor from the breather and cleaned it. Put it back in and took a test drive and everything is good now. It was filty so I may go ahead and replace it with a new one.

 

That does make sense.

If the IAT was filthy, that tells me your air filter is not doing its job. You using an oiled filter?