Help!!! Erratic revving..Motor is going nuts

Notched90

New Member
Sep 9, 2005
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Last night while doing my first burnout in a while, I seemed to have cracked a vacuum hose or damaged something that is causing my engine to go crazy. I searched the posts but didnt find anything that would help. Ever since last night my motor will:

Idle really low (550 rpms) then shoot up to 3200 rpms and hang there for about 20 seconds, then drop down and come very close to stalling. It goes nuts and revs itself up and down in between.

I checked everywhere for vacuum leaks, even using the old carb-cleaner method of spraying in potential vacuum leak areas and listening for a response in rpms. I checked every hose I could think of, and the only one that is actually cracked is the line coming off the EGR valve which was cracked prior to this.

Sound familiar?? I know this is very vague but I can't find the source and I can barely drive my car in the mean time....
 
Do you know how much vac you are pulling? A stockish motor should pull nearly 20" hg.

What happens if you disconnect the IAC on a hot motor (for testing only, since this could lead to stalling depending upon how you set your idle)?

Good luck.