Hey guys, I got a small miss and I figured this forum would be a good place to start.

I got an 03' F-150 FX4 with the 5.4 recently from my dad and it just started missing at idle. It only does it sometimes. I changed the spark plugs, cleaned the k&n filter, and cleaned the MAF. I don't know much about these motors(I'm a pushrod guy) and was just wondering if it could be one of the coils? Also, no check engine light is on.

The truck is in excellent condition (1 owner) with 51,000 miles and garage kept.

 

could be a coil going bad, could be a vacuum leak, bad fuel filter, tps going bad. how does it run under acceleration any misses then?

 

It doesn't miss under acceleration, only at idle, and intermittently.

Fuel filter was changed with the plugs, also have checked vacuum lines.

Not sure how to check the tps on these, I know my mustang it requires .98v. to the green wire.

How would I check the coil, just keep replacing until I find the bad one?

Thanks for the fast reply.

 

unfortunately, if its not throwing any codes so its a crap shoot on the coil packs until it does throw a code. most likely its a failing iac valve. you can clean it, but its only a temp fix until it breaks again. if that doesn't work clean out egr valve. lol these kind of problems suck because your chasing a ghost