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View Full Version : Strange idle after motor teardown

Rouseman
11-07-2010, 12:45 AM
Hey guys. So last week i posted that i was going to be doing a head gasket change... everything went well and the car runs great but the idle is very weird its slow and sparaticly moves between 900 and 1000. However this is ONLY when its stopped at a light or parked. Standard driving is good. Any ideas? did i miss some Houdini vacuum line?
Gr1m
11-07-2010, 12:51 AM
Sounds like a vacuum leak, u sure everything is running fine under load?

I'm hoping you did clean off all of the old gasket from your heads/manis/TB/egr and resurface it with some emery paper to get a nice tight seal, did you do any of that?
Rouseman
11-07-2010, 09:34 AM
Yes i did do any of that and yea iam sure its fine under load.
xXManwhoreXx
11-08-2010, 02:41 PM
Idle throttle position sensor?

idk what the acronym is for 3400's
alerored04
11-08-2010, 05:30 PM
Did you reuse the tb gasket? I had that happen once when I reused a tb gasket. It had a small tear that was causing a vacuum leak.
[ion] C2
11-08-2010, 05:59 PM
Idle throttle position sensor?

idk what the acronym is for 3400's
Same thing it is for every car.

IACV (Idle Air Control Valve). It's not a sensor, it's a valve that does whatever the PCM tells it to do, based on other sensors. Sounds like this is either unplugged or otherwise stuck/dirty, or you have a vacuum leak. Pretty much the only things that would cause this situation.
Rouseman
11-08-2010, 08:54 PM
hmm.. alright i will check the sensor... as for the gaskets i got the felpro set from advanced and i changed ALL the gaskets that came with it including the throttle body one but i will check all of them.
Gr1m
11-09-2010, 12:16 AM
did you remove your fuel rail from your lower manifold? (not that you have to in order to do the head gaskets) but if you did then you might have a torn injector o-ring causing a vaccum leak. i just had this.
Rouseman
11-09-2010, 12:19 AM
did you remove your fuel rail from your lower manifold? (not that you have to in order to do the head gaskets) but if you did then you might have a torn injector o-ring causing a vaccum leak. i just had this. yea i did actually but i checked em all before i put them back..still ill check this as well.