surging at idle

[Anker]

Originally Posted by seningen

Also to check your AOS -- you can undo the oil fill cap and see if there is a suction on the fill tube. If so, that's usually an indication of an AOS issue.

No suction on the oil fill cap when running is an indication that there is an air leak in oil fill tube. There should be suction, but not enough to prevent you from unscrewing the cap. If you cannot unscrew the cap when the car is running its an indication that the AOS is bad.