Thanks, I am scheduling for next week to check head...,,I will post results.

Wouldn't that show up on a compression test?

I have a 2005 Ranger 103000 miles 3.0 cyl. 4 misfire....it only misfires at idle after engine warms up. Misfire will go away at about 1300 rpm. I have done everything I can think of. Tune up (plugs, wires, coil) swapped fuel injectors, vacuum smoke test, compression test, leak down test, cleaned MAF...