Engine Revs Unintentionally

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Dec 25, 2009 | 03:04 PM

#16

detroit pistins

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From: Detroit

Quote:

Originally Posted by Betty

I've noticed this problem when my engine is still cold too. When I first start my engine it idles at 1500 rpm once it warms up it drops to about 1000 rpm. But then when I'm at a stop light not even steping on the gas my rpms go up from 1000 rpm to about 1350 rpm. After like 4 seconds it stops and goes back to normal at 1000 rpm. It stops doing this after the engine is fully warmed up. Is this normal?

I have been having the same issue, even when its warmed up, when i come to a dead stop, throw it in neutral, and the rpm sometimes goes from 900 rpm to about 1000-1100 then drops down to 900. not sure what to check for either.
would a leak in any of the piping couplers cause this?

Dec 25, 2009 | 03:08 PM

#17

1qwikef

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From: maryland

it looks like the throttle body has a idle air control valve on the bottom of it. i would try to take the t/b of and remove the aicv and try to clean everything good and see if that helps
here is a pic of a stock t/b
http://tdi-plc.com/blog/wp-content/u...2633-small.jpg

Dec 25, 2009 | 03:48 PM

#18

sktng22

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From: Northern NJ

sounds like mass air flow sensor or a leak in the vacuum somewere

Dec 25, 2009 | 07:01 PM

#19

Kemist

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From: Windermere, Fl

mine did this when the inc went bad, $400 at the dealership. found one on here for $135, just fyi

Dec 25, 2009 | 07:08 PM

#20

detroit pistins

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From: Detroit

inc?

Dec 25, 2009 | 07:18 PM

#21

Kemist

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From: Windermere, Fl

Quote:

Originally Posted by detroit pistins

inc?

sorry, iac.. idle air controller . like the guy said a few posts up, but its easy to get to and you don't have to take the TB off. If you have a friend with an evo, just swap the sensor ( 3 screws and 10 minutes) see if that solves the problem

Dec 25, 2009 | 07:21 PM

#22

localtoys73

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From: deltona

same issue as everyone else

also had this on my toyota truck, cleaned out the TB with some carb cleaner and it fixed the problem on the truck

havent messed with the car yet

Dec 25, 2009 | 07:23 PM

#23

detroit pistins

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From: Detroit

sorry for the noobiness but which one is the iac

Thanks

Dec 25, 2009 | 08:19 PM

#24

1qwikef

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From: maryland

Quote:

Originally Posted by detroit pistins

sorry for the noobiness but which one is the iac

Thanks

it would be #2. # 1 is the tps

Dec 27, 2009 | 03:44 AM

#25

tim85851

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From: Madison, WI

Quote:

Originally Posted by Betty

^^^ Tim85851 that is my exact issue. I just started noticing mine. How long has yours been doing it for? Any help on fixing the issue.

mine has been doing it for like a month or two...mainly when the engine is cold...then it stops...ill check all the vaccuum lines near the throttle body area...

my tuner told me to zip tie all the vaccuum lines and i think im gonna do that very soon especially since my car is just chillin in my garage away from the snow (until i re-instate the insurance)...

Dec 27, 2009 | 05:09 AM

#26

delongedoug

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From: CT

Quote:

Originally Posted by detroit pistins

I have the exact same issue.

Dec 27, 2009 | 11:12 AM

#27

detroit pistins

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From: Detroit

ya iam also have a boost creep issue, so not sure if there if there is some kind of leak that is related to all of these issues.

Jan 31, 2010 | 11:40 PM

#28

tim85851

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From: Madison, WI

bringing this one back from the dead...any updates?

ive been driving my evo again and it still does this unintentional revving but not all the time...ill try to take some video of it and post it up...

Feb 1, 2010 | 03:26 PM

#29

chinto

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From: New Jersey

if you have a/c even if you dont have i turned on it may be cycling on and off ( clutch kicking on and off for the compressor ) causing the rpms to go up and down.

Feb 1, 2010 | 04:37 PM

#30

detroit pistins

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From: Detroit

Quote:

Originally Posted by tim85851

check ur vac lines , u might have a leak somewhere.
in general tho, people with mods that havent had thier cars tuned, would encounter this especialy with aftermarket intakes.