Donnie's GTS

Lately I have been having this intermitent vibration coming from the engine bay, and finally caught it and determined its coming from the intake, so somwhere in the intake parts. So while driving when this vibration happens, the rpms will hang at 1500-2000, and a quick rev will get it down back to normal same thing sitting at a light. My question it can this be as simple as a bad IAC valve? Or do you guys think its much more serious than that.

y2kStangGT

when you start your car in the morning does the rpm drop dramatically and the car stall? if yes then your iac valve needs to be replaced.

GhostRider02GT

typically when the IAC goes bad, or at least on the few cars I have worked on, they dont stay idling

trickdriller

This is pretty elementry for the subject, but does your car do that only when the a/c or defroster is on? Or is it at all different times?

I SwearItsSlow

so it should take a little while then to drop? i just want to clarify because if so, mines all good and thats good to know.

Donnie's GTS

what it does, is raise and hang at about 1500-2000 rpm, and then die, a quick rev solves it, but when in 5th gear cruising at 40, the car started to slowly accelerate when experiencing these symptoms. Now the check engine light came on for a brief period, but got that checked and it was a forward o2 that was slow to respond, so I doubt that had nething to do with it.

anyone have any ideas???

Donnie's GTS

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devore86

My car has a similiar problem, it idles rough going between 500 and 750 in all gears( auto) it is worse with my AC on???????

You think my IAC or TB are dirty????????

qpHalcy0n

Itll usually throw a lean code and possibly an O2 code. What yours is doing is pretty much what mine did. I ended up just taking the entire plenum off and the IAC out and spraying some carb cleaner in it. Never happened again.

Donnie's GTS

I did get a forward o2 code, but it was that it just responded slowly, so thats nothing, i think.