A little more help please. I have an 02 deville. Started this high idle thing about 2000 miles ago (but started out only doing it sometimes). Then recently the Check Engine Soon light came on and stays on and it is doing the high idle thing almost all the time now (but not all the time). After reading the posts I first disconnected the battery to let the system reset. No change. Then I sprayed some brake cleaner around the plenum while it was running and it slowed the engine idle. So, it looks like I've got a leaky plenam. I can fix that, however, is there anyway to do it without taking off the manifold? I haven't read of anyone else having the high idle (1500) thing. Are the two symptoms unrelated? It runs smooth when driving. Thoughts? Thank you, Scott

The job cannot be done without removing the fuel rail, injectors, harness, and intake manifold, as the plenum is the connector between the throttlebody and intake manifold and there is literally NO way to remove it otherwise.

It's not a bad job......a set of fuel injector seal O-rings (aftermarket) and the plenum (dealer). The intake manifold gaskets are supposed to be reusable, but you might want to replace them, too.

For the plenum try www.gmpartsdirect.com , www.gmotors.com. For the O-rings and gaskets try www.rockauto.com. If you want to get it all from one dealer, try Luke in parts at Lindsay Cadillac, over there -------->