High Idle when cold
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Senior Member
Joined: Jun 2007
Posts: 251
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From: Clearwater, FL
Car: 92 Camaro RS
Engine: 305
Transmission: Auto
Axle/Gears: Stock
High Idle when cold
I know there ar elots of threads about incorrect idle speeds etc but most seem to have multiple symptoms and are on quite different cars.
Mine is a 92 Camaro RS 305 TBI.
All stock except flowmaster muffler and K&N filter.
it will idle at 1000-1500 when cold, but once it warms up it is perfectly normal (about 700 or so). It idled normally for the first few months.
NO other symptoms, and no codes.
Any ideas?
Mine is a 92 Camaro RS 305 TBI.
All stock except flowmaster muffler and K&N filter.
it will idle at 1000-1500 when cold, but once it warms up it is perfectly normal (about 700 or so). It idled normally for the first few months.
NO other symptoms, and no codes.
Any ideas?
Senior Member
Joined: Jul 2007
Posts: 1,461
Likes: 1
From: Manchester, CT + Nashua, NH
Car: 90 Firebird Formula
Engine: LO3
Transmission: T5
Axle/Gears: 3.08 one wheel peel
Re: High Idle when cold
Im pretty sure its supposed to idle high when its cold. Thats why you have the Idle Air Control valve. it allows the ECM to control your engines idle rpm to warm up.
My car does the same thing. It idles at about 1500 right after start, and slowly works its way down to abou 700 RPM over 5 minutes of sitting. When driving, it idles at 700 untill it gets past 180* then it idles at 500 when fully warm with the clutch in.
My car does the same thing. It idles at about 1500 right after start, and slowly works its way down to abou 700 RPM over 5 minutes of sitting. When driving, it idles at 700 untill it gets past 180* then it idles at 500 when fully warm with the clutch in.
Thread Starter
Senior Member
Joined: Jun 2007
Posts: 251
Likes: 0
From: Clearwater, FL
Car: 92 Camaro RS
Engine: 305
Transmission: Auto
Axle/Gears: Stock
Re: High Idle when cold
no no no, I live in FL, air temperature is never "cold". I mean when the engine is cold.
I disagree, it should NOT idle at 1500 RPMS just because the engine is not warmed up. Maybe if the air temp is freezing, yes.
But when I go and start it in a minute it will idle high and it is 70 degrees....I do not think the air temp is causing it.
I disagree, it should NOT idle at 1500 RPMS just because the engine is not warmed up. Maybe if the air temp is freezing, yes.
But when I go and start it in a minute it will idle high and it is 70 degrees....I do not think the air temp is causing it.
Thread Starter
Senior Member
Joined: Jun 2007
Posts: 251
Likes: 0
From: Clearwater, FL
Car: 92 Camaro RS
Engine: 305
Transmission: Auto
Axle/Gears: Stock
Re: High Idle when cold
I do appreciate these points, but just to clarify a few reasons why I don't think it is purely air temp causing this.
Mine started doing it over night. It never did it before (maybe 1000RPM for 30 seconds). The air temp has only dropped from 80 to 70, it is still nowhere near "cold" and mine will idle high all the way to work (20-30mins)!
I have to keep my foot heavy on the brake at the lights all the way, to not rear end people. I don't consider that normal. Unless maybe, like I said the temp is freezing, but it is nowhere near cold.
Mine started doing it over night. It never did it before (maybe 1000RPM for 30 seconds). The air temp has only dropped from 80 to 70, it is still nowhere near "cold" and mine will idle high all the way to work (20-30mins)!
I have to keep my foot heavy on the brake at the lights all the way, to not rear end people. I don't consider that normal. Unless maybe, like I said the temp is freezing, but it is nowhere near cold.
Supreme Member
Joined: Sep 1999
Posts: 7,072
Likes: 13
From: Philly, PA
Re: High Idle when cold
Throttle cable not allowing the throttle to close fully would be one explanation- could be held up on something, possibly.
If you're talking real engine issues then I'd get a scan tool on it and see if anything's reading odd. Like a CTS (Coolant Temp Sensor) that's reading significantly lower than actual. Or a bad TPS (Throttle Position Sensor).
Last would be something like maybe the IAC (Idle Air Control) unit being bad and not allowing it to idle down, or possibly.... a simple vacuum leak.
That would be my short list.
If you're talking real engine issues then I'd get a scan tool on it and see if anything's reading odd. Like a CTS (Coolant Temp Sensor) that's reading significantly lower than actual. Or a bad TPS (Throttle Position Sensor).
Last would be something like maybe the IAC (Idle Air Control) unit being bad and not allowing it to idle down, or possibly.... a simple vacuum leak.
That would be my short list.
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From: Milwaukee, WI
Car: 1984 z28
Engine: BBC
Transmission: TH400
Re: High Idle when cold
I do appreciate these points, but just to clarify a few reasons why I don't think it is purely air temp causing this.
Mine started doing it over night. It never did it before (maybe 1000RPM for 30 seconds). The air temp has only dropped from 80 to 70, it is still nowhere near "cold" and mine will idle high all the way to work (20-30mins)!
I have to keep my foot heavy on the brake at the lights all the way, to not rear end people. I don't consider that normal. Unless maybe, like I said the temp is freezing, but it is nowhere near cold.
Mine started doing it over night. It never did it before (maybe 1000RPM for 30 seconds). The air temp has only dropped from 80 to 70, it is still nowhere near "cold" and mine will idle high all the way to work (20-30mins)!
I have to keep my foot heavy on the brake at the lights all the way, to not rear end people. I don't consider that normal. Unless maybe, like I said the temp is freezing, but it is nowhere near cold.
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Thread Starter
Senior Member
Joined: Jun 2007
Posts: 251
Likes: 0
From: Clearwater, FL
Car: 92 Camaro RS
Engine: 305
Transmission: Auto
Axle/Gears: Stock
Re: High Idle when cold
well I TRY to not make every post that long as then no one bothers to read them.
I also did say it is not pulling any codes so I am leaning more towards needing to adjust the IAC or TPS too...rather than something that significant being plain broken...I'll check those and the throttle cable etc...although that seemed fine when I cleaned the TB a few months ago...u never know.
thanks guys.
I also did say it is not pulling any codes so I am leaning more towards needing to adjust the IAC or TPS too...rather than something that significant being plain broken...I'll check those and the throttle cable etc...although that seemed fine when I cleaned the TB a few months ago...u never know.
thanks guys.
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