There are check valves in the corrugated hose as well. If both of those others are in place, I reckon one of those might be bad.
Wouldn't hurt to run a compression test as well.
Wouldn't hurt to run a compression test as well.
Yeah I did the compression test and leak down test and passed both so it has to be the intake manifold right?Check compression!
Also might want want to pull the intake and really get a good look at the red check valve... trash from shitty oil can hold it open.