HELP PLEASE: Engine Idle Problem

Originally Posted by 6SPD_FTW

That's the fresh-air feed for the PCV system. 80% of blow-by that gets past the piston rings is fuel vapor. Manifold vacuum sucks the fuel vapors out of the crankcase, and your kinked off hose is what allows fresh air to circulate into the crankcase so that a vacuum doesn't build up in there.

The ECM doesn't really have a way to monitor the PCV flow, per se. It is figured and programmed into its little brain to know how much flow at X rpm and Y load.

So, if that hose is kinked off, then the PCV flow is WAY less because it can't draw in fresh air to restore what the manifold is sucking out. And proper PCV operation is EXTREMELY important to a smooth idle!

So, the bizarre idle you're having, I will say with 100% assurance, is definitely the kinked off hose. Just sayin...

Late,
Trav