Granddad aparently had this problem with an old chevy cheyenne years back and went so far as to tear the motor apart. he found a chunk from either the valve or piston sitting on top the cylinder. I dont know how that is as it was before i became a twonkle on moms eye lol. thats what made me think back to what bill said. that Sounds like carb cleaner? I'll get a can of b-12 while I'm at the parts house tomorrow getting plugs and see what happens. Phoenix has a dr appt Monday. So I have to be able to drive my truck dice they will be in Durango all day