I have a 99 f150 with 4.2l v6.4x2, since I bought the truck it's has a misfire every once in awhile never any kind of pattern just random sometimes not at all, no engine lights no codes it's been getting worse lately but it's only at idle most of the time, sometimes it will buck when excelerating but it's mainly at idle it's still got power idk wat it is. The plugs and wires have been changed and I read that if it's a coild pack the CEL would be on any help greatly appreciated

 

They dont always throw a code but it still may be storing one. Have you actually had it on a reader to see if there is a code?

I had a coil completely dead and not throw a CEL but there was a stored code in there letting me know what cylinder it was.

 

I had a misfire on cylinder 2 for about a month with no code.

It finally threw a code and i was able to read it with my programmer.

Changed the spark plugs and wires and I was good to go.

If felt like the Trans was slipping to me but turns out it was a missfire.

 

I'm gonna go throw it on OBD2 right now I'll keep posted on wat the outcome is hopefully good news cuz I already replaced plugs its got E3s in it now and the wires are aftermarket coils I believe are untouched not sure