99 F250 with a 5.4 I found broken timing chain guides and replaced chains guides and teninors. Still had a running problem after it warmed up and found 3 bad coils. After it sits a while warm or cold it has a shake to it like another bad coil but it goes away after about a mile. It hasn't set a code just wondering if there might be another bad coil or if it is signs of something else.

 

I would check all your spark plugs to make sure there tight.
I would also double check all connections to the coil's.

 

good advise cubantech!

 

Clean your IAC.