Originally Posted by
zip439
Also the Evap leak may be feeding into this problem as vacuum leaks will indeed cause bad idle.
Yea, I overlooked that, the hose to the purge solenoid/valve would be suspect in this case. If it is leaking, then you have a vacum leak.
But one way to verify a vacum leak is this:
With engine idling, yank off the oil filler cap. If the engine sputters and runs WORSE, you have no substantial vacum leak.
If putting the cap makes NO difference, you have a hell of a vacum leak.