Follow-Up to my previous post about the enging dieing out on me and running like crap (weak, sounds funny, smoke coming out of exhaust.) This motor only has about 25-30k miles on it, but won't be under warranty. The dealer replaced my first motor due to butterfly screws coming loose on intake manifold. Now This motor has already crapped out on me, *sigh*

I ran compression tests on all my cylinders. The rear bank cylinders are strong, at 195, 200, 190; but the front bank cylinders are weak and only testing at 120, 138, 150. Any ideas what could be causing this or what to check? I also noticed the weak bank of cylinders has oil/film build-up on the intake manifold runners.

Thanks for any help or suggestions.

 

Try putting a little bit of oil (a tablespoon or 2) in each spark plug hole (for the front bank only), let it sit for a bit, then do the compression check on those cylinders again.
Usually if the compression increases dramatically, it's indicating worn piston rings or possibly a crack in them... if not, usually valve guides or head gasket.

Beware after you reinstall the plugs/coils and start her up, there'll be a ton of oil smoke coming out the exhaust (it'll be almost like using SeaFoam, except it smells worse )

 

Okay, I just got done testing that by putting a cap-full of oil them, it only raised the compression of each cylinder about 10-15psi so it's not the piston rings.

Thinking head gasket or valves...