I just cleaned the throttle body because my engine was surging again, and was wondering about the idle air passage.

There is the hard plastic tube that goes from the bottom of the t/b to the top of the engine, to a solenoid (next to the boost bypass solenoid) and then another hard plastic tube that goes somewhere behind the engine. What does that go to? How do I clean those?

When I took the tube off of the t/b and front of the solenoid (not the tube going behind the engine) I noticed some oily substance on the nipple. Do you think that inside the solenoid there is a build-up of gunk causing the surging?

I'm just getting really sick of cleaning the maf and t/b but still having the same problem. I also checked for vacuum leaks and found none... so... any help would be great!

 

Sub'd

 

sub'd for nothing apparently...

 

those are evap lines.tank fumes go through there.idle is controlled by throttle plate position.the oil is probably from your pcv vent tube which sucks crankcase pressure back into the intake.its normal for a little oil to be in the intake,blower and intake manifold.alot of people run catch cans which catch the oil before it hits the intake