I have a 1997 F-150 2WD w/4.6l v8 with 265,XXX miles.

I'm haing an issue where I will run fine (no error codes) for 60-70 miles or so. I'll park and get back in to go and the engine will run rough and usually reports a misfire on either cyl 1 or 4. (p0301 or p0304).
So far I've replaced;
- the plugs
- the wires (twice 1st time with cheapo's then with nicer wires)
- both ignition coil packs
- cleaned the MAF sensor

Since it does run fine for awhile, I'm guessing its a heat issue? Should I be looking at a new ECM? Replacing a fuel-injectors?

Any thoughts or ideas are greatly appreciated.

Thanks in advance
Dave

 

i guess make sure the wires are still on the plugs all the way for starters. what brand wires are on it now? did you use dielectric grease on the boots? what brand plugs? did you gap them all?

 

Yeah the wires all click when I pull them on & off.
I used Champion plugs gapped to .054
The first set of wires were O'Rielly house brand, the set thats on them now are Borg-Warner.
I did put di-electric grease on, although with all the checking I might need more.

-dave

 

i'm not to familiar with barg warner wires so i cant say anything there. i believe champion plugs are good for these engines but not totally sure. explain exactly what you mean when you park and get back in. like do you go to a store and leave the truck running and a couple minutes or seconds later you get in and it starts to miss on one or the other cylinder or both. or do you shut off the engine before you leave the truck. in 60-70 miles the truck will be completley warmed up so i dont think its a heat issue. did you check for any vacuum leaks or your pcv hoses and elbows to make sure everything is alright? and have you pulled the plugs that are misfiring to see if anything is wrong with them?