My 94 F150 6cyl was exhibiting seeming random periods during which it would run rough, sometimes when moisture is present but not always. At times the check engine light would come on. My mechanic finally got some codes, which indicated either the computer or the air temperature sensor was to blame. I have already replaced: plugs, wires, distributor cap and button, MAF sensor, PCV, fuel filter. As of yesterday after I replaced the MAF sensor and plugs and wires (one at a time so as to not mess up the order), it was idling rough without a check engine light coming on.

Suggestions?

 

94 has a MAF? I thought those were still speed density.

 

Manual shows a MAF, symptoms fit mine, and the part I bought at the parts store slightly improved the problem but did not cure it entirely.

 

No MAF (mass air flow) on 94 300s. Only in 96 did they recieve the mass air flow. Maybe the MAP (manifold absolute pressure) sensor.