Hey guys and gals,

Having a little issue with my 2002 F150 4.2L automatic 4X4. After a good rain storm, the truck starts rough. Idles fine but as soon as you put it into gear and accelerate it runs rough again. Once it's dried out, runs fine. The truck has 227,000. No COP, just one coil pack. I'm not sure when the plugs or wires were last changed. I know the truck was well taken care of. Any suggestions on where to look first? I don't have the money to just start replacing parts. Need a systematic way to find what's causing this. No CEL either.

Thanks.

 

I had a truck that had same issues a few years back and it wound up being a crack in the rotor cap. Moisture was leaking in during damp periods and causing rough idle and a rough ride, after it dried out it was fine. Old cracked plug wires can also cause same kind of problems. Hope this helps... James

 

Thanks for the advice. I'll give it a check tomorrow.