Thread: runs rough

I have an 04 f150 5.4 and I'm having problems with the #8 cylinder. The coil pack went bad so I replaced it and now it's reading a miss fire so I replaced the spark plug and the one I took or was melted away. So with a new coil pack and plug it's still giving me a miss fire code. The codes that I get are as follows p0174, p0308, p0316, and p0316. What could possibly be wrong? The truck has 149,000 miles and I just changed the plugs last summer.

I have the 4.6 triton and mine was idling really high then really low at the same time. I had the throttle body replaced. Could that be your problem?

U could pressure test the cylinder. Might have a head gasket going and the moister is kickin ur coil. Happined to my 03. Leme know how u make out bud