Finally got it beat. It was the throttle body. One thing to note about the IAC is that it only controls the cold idle. So, if the idle lowers when warm then the IAC is infact working. What the issue was in my case was that the throttle body no longer closes (and seals) properly (300K KM will do that...

Hey SG. I am having the same issue with the high idle and P0505 codes, (05 Matrix XRS) Vacuum leak checks were done. (none were found) TB and IAC were cleaned. (no help) IAC has been changed twice (mechanic thought the first one was bad out of the box) and the mechanic has now given up (wasting to m...

Hi guys 1st gen Matrix XRS (05) owner here. Need to know where to take this machine for some work. High idle issue P0505 CEL, been at the mechanics for a week, they've cleaned, and now replaced the IAC twice (thought they got a bad one the first time) but still 2000+ RPM (higher when cold) Fuel rati...