My 1997 F150, 4.6l has developed a miss/backfire on startup, which then goes away after warmup/driving about 5 miles. Coughs, spits and chugs until warm, and won't pull for $**** (lurches/hesitiates).

I figured maybe a plug; changed all this weekend. Seemd to run fine for a day, then the miss returned.

My plug wires were replaced less than a yr ago (NAPA set), but I suppose it could be a bad wire.

Coil packs?

In the afternoon, after work, truck seems to run fine, but miss returns in the morning again.

No check engine light.

Any threories about what to try next would be appreciated.

Thanks!

 

it sounds like your problem is temp related.

the coolant temp sensor is known to cause problems like this. make sure your coolant level is good and there is no air in the system.

it sounds like something is telling your engine to run super lean.

just a thought-

 

OK...so where is temp sensor for coolant system? Sounds logical.