I have a 2001 f-150 5.4L 4x4 with 117k, truck runs great but at idle its beginning to have slight shake to engine. I have replaced spark plugs ( motorcraft) and the pcv valve, but has not corrected problem any one have a suggestion

 

Have you checked for codes? AutoZone will do it for free.

 

It might be your coil packs.

 

I would start with the Coils, then make sure the IAC isnt all clogged up.