Great thoughts gentlemen. One detail that I had mentioned before is that this last round the truck is running bad with no codes coming from computer. This unlike the previous times when the truck threw the code that the plugs were bad, this time after changing the plugs, the truck ran bad, the code went away and didnt come back.

The mechanic didnt tell him how the plugs were fouled, just that this was common in the ranger.

I agree that more needs to be researched, I just hoped that someone may have had this same experience and know the most likely part to start with in this case.

Thanks to all!

Dave