New C5 Vette Idle Issue
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Teching In
Joined: Dec 2009
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New C5 Vette Idle Issue Morning guys! I'm inprocess of purchasing a 98 6MT Vette Coupe. It's got a few mods...cam, intake, exhaust, RAM clutch, and a few other things. Th previous owner had the car tuned and it runs really well. But once its warm, the idle will surge up to about 1500rpm, and then back down to 500-600. I know its not the cam loping...cuz i can hear that too...but it seems to be surging. I've tried to search on here and other places (the search feature wont work on this site). I've found information that suggests its either an IACV, or TPS...Possibly a vacuum leak? Any help would be greatly appreciated.
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
There are several things that can lead to a surging or inconsistant idle even when stock. Toss in the fact that the car has a cam and custom tune and you've got a whole world of possibilities.
First, did the motor ever idle correctly post-cam/tuning install? This is important to know, if you can find out from the current owner. Reason being, no point in throwing parts at the car if the real problem stems back to the tune.
First, did the motor ever idle correctly post-cam/tuning install? This is important to know, if you can find out from the current owner. Reason being, no point in throwing parts at the car if the real problem stems back to the tune.
another possiblity is the idle air control valve, but most of the time they've been known to cause idle surge like that on startup as well. it's definately worth taking a look at. but they can get prreettyyy pricey depending on the vehicle. good luck!!
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C5's are fly by wire, there is no IAC Valve.
