94 F-150 300 Missing

[mtnman57]

I have developed an erratic miss at a constant speed thru all ranges. I have checked or replaced all the easy stuff. Plugs, wires, fuel filter,fuel treatment, cap and button. It seams to be more pronounced at normal operating temp. Been driving for two weeks, not getting better or worse.

[1saxman]

I don't know exactly what it is, but chances are it's in the electronic area. Either ignition or engine control chip. I had something similar once that stumped everybody, and it turned out to be corrosion in the coil wire.

[bradrhale]

could be a coil breaking down.

[delkins]

have you checked or replaced the air filter? This sounds like a mixture misfire not electric. Check for vacuum leaks and or stuck open or closed injectors. Its a ford, good luck.