Hissing (Vacuum Leak?) from around TB after LIM gasket install [Archive] - GrandAmGT.com Forum


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05-30-2004, 07:35 PM
Hey all, I put back the wife's 99 Grand Am GT and started it up. It started rough and then idled rough and there was a loud hissing sound coming from around the throttle body. The SES light is on and it runs better when I give it gas up to 3k rpms but still has the hissing sound. So I am assuming that it is Vacuum leak, but I cannot pinpoint it. Her car has 50k miles on it and I just realized that the PCV has never been replaced, so I'll replace that. But it didn't do this before the LIM Gasket install. It sounds like it is coming from the vacuum hose on top of the thing-a-ma-bob on the end of the front fuel rail.

So, any ideas? I'm gonna scan the car to see what DTC is giving the SES light tomorrow.

Thanks in advance!

UPDATE: Fixed it. Scanned it with ODBII and the cyl 6 injector was not firing. Took the UIM off and greased the O-rings on the FI's......and all is good now. Sweet!