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Bouncing idle - Couldn't find exactly what I was looking for with search

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Old 05-07-07, 01:25 PM
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Bouncing idle - Couldn't find exactly what I was looking for with search

Anyways, car just started doing this the other day ...
It seems to have lost a bit of power and not boosting as hard as it used to.
Runs a little rich
and now when warm it will idle at 750 for a bit then drop to 300-400 ish and bounce between.
Also to be noted, if I have my interior fan on at speed 3 or 4, the engine will idle higher.. so when its drawing more current the engine just wants to idle higher... it has always done this.

I don't know if it is connected but maybe....
my car also makes that Moo'ing sound... no idea if that is related either

It should be noted that this car is an automatic.

Thanks,
Pauli
Old 05-07-07, 01:41 PM
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Mine does the idle loop and it has a blown water seal so you may want to start there. Other than that, check you injectors. Could be getting too much or too little fuel. Post your engine specs. Miles/rebuild stuff like that.
Old 05-07-07, 03:19 PM
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64k miles on engine...
apexi intakes
HKS downpipe
RB exhaust.. most reliability mods
stock ECU
Old 05-07-07, 09:38 PM
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Check to see if the vacumm line popped off the boost sensor on the firewall...
Old 05-07-07, 10:09 PM
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you may have leak in your IM gasket. Get some carb cleaner and spray around that area, and while you are at it spay around all the vacuum hoses. If your car dies or changes in idle you found your culprit.
Old 05-08-07, 12:04 AM
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Issues?

I would spray around the LIM and check for lines by the firewall. Also, that "mooo" sound is caused if you removed your air pump.
Old 05-08-07, 09:43 AM
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Guys, a vac leak would raise the idle.
It sounds like the problem I'm currently going about. I would replace the injectors with some flow matched ones. If you need a set I have a bunch of them. The price is 120 shipping and paypal fees included. I'm sending out my 850's and 1600's when i get time to tear them out.
Old 05-08-07, 02:18 PM
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Update:
Upon investigating further, it seems the vaccuum is bouncing somewhere between 17-13 at the same time the rpms are going between 300-400-750.

If I go WOT for a bit and let it de-rev it smooths out for a bit then goes back to the same pattern.
I definately had WOT in 3rd on the auto and it wasnt boosting any higher than 4..
the mooing sound is coming from the tube that feeds the intake from the airpump.... but its the apexi intake... is it still supposed to sound like that?
Old 05-09-07, 12:13 AM
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sounds like low compression
Old 05-09-07, 08:55 AM
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Well I took a couple videos of the car and you can kind of hear the rough idle but I also took a vid of the boost gauge and you can see the needle bouncing as well

I'll have em on later today but thanks to those who are giving this some thought
Old 05-09-07, 09:38 AM
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If hes pulling 17in vacuum at 750 I wouldn't call that call that low compression. Great vacuum is 18 at idle. I would first check the tps adjustment. If you cannot get it within spec the sensor is corroded inside. Other than that the only other think i think it could be is injectors...
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