I watched the video. Very interesting. Thanks

 

I would look at the Long Term Fuel Trim on both banks and determine which side is lean; then unload the pistons with either disconnecting a plug wire or injector - whichever is easier - and listen for a change. If nothing, I would check compression with a gauge, next in line.

It sounds air-like or pneumatic looking at the video. .

 

Hi MLD, yes, I've done that. I narrowed it down to Bank 1. The O2 sensors after the Cat confirm a Lean condition on Bank 1. The second part of your suggestion is a bit more difficult. The sound of the engine doesn't allow for an easy way to listen for a significant change. I'm going to try the shop vac method to see if I can eliminate at least some of the exhaust leak sound.

Thanks for the suggestions.
Calixto.

 

If you have normal compression on each cylinder, then the head gasket is good, and the valve train is working fine - i.e., it pumps up to full compression in steps. No sound change means the bottom end is fine..

It must be a leak at the exhaust manifold, then..... good luck on getting those nuts off the studs if that's really the culprit. It might snap the studs requiring angle drilling them out.

 

I thought of that...I've taken out exhaust bolts before and had to heat them a lot, so a snapped bolt would be a real possibility.

Thanks!
C