Ok had the old girl out for some errands today before hopefully some rain/snow comes and helps put out these fires. Left a clients house and car was idling very rough and surging to 1200 back down repeatedly. Fortunately was close to the shop who I have work on the car. Took off the air box and it sounds like a shop vac sucking air from under the intake manifold. So going in for a better look in a week. do a smoke test and look for the leak. Any guesses as to what could be under that manifold big enough to make that loud of a sucking sound. It's definitely not some little 1/4 inch vacuum hose. Could the manifold be cracked or is there something bigger running under there we couldn't see? Whats your guess all you veteran wrenchers?

P.S. he did pull codes and there were a few. But nothing throttle body/intake related, couple of intermittent misfires and the O2 sensors doing a sporadic code trip.

DKP