[cewtwo]

Forgive my lack of technical jargon. My RV had a similar problem when I first got it.

I took the intake manifold off of the engine to see what was happening. There was a large carbon deposit just under the Intake manifold. If it would have fallen into the engine, it would have destroyed the engine. During a repair prior to my haveing the RV, there was a gasket above the intake manifold that had two openings for a pollution control device. They ignored those openings. They installed a gasket that just covered them. The carbon deposit was what resulted from that glaring lack of technical care.

I put the proper gasket on, re-installed everything and it ran fine after.