1991 Pontiac Firebird High Idle

1991 ALL OTHER MAKES ALL OTHER MODELS
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91FIREBIRD305
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Its a 305 with 171 miles on it,
The car was owned by a buddy of mine and I finally bought it from him :D
Well finally for my question,
When I start the car it idles high, around 1000 rpm or higher, I have to let it sit for a few before i can drive it so it will idle down, kinda sounds like a miss in it also, thats just when its in idle, it drives fine, the tranny jerks into gear when i go into reverse, or over drive.
The wires were changed, but he said the plugs looked brand new when he checked them, anyone know how I could fix the idle problem?
Jul 2, 2006 at 10:20 AM
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91FIREBIRD305
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Let me get into more Detail,

At 8am this morning I start her up to get to work, she idles above 1000 rpm's and about five mins later she idles fine.

Someone has to know something?

Sorry for sounding like a @$$, but i need some help.
Jul 3, 2006 at 2:49 AM
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91FIREBIRD305
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[quote:530865ffdd="91Firebird305"]Let me get into more Detail,

At 8am this morning I start her up to get to work, she idles above 1000 rpm's and about five mins later she idles fine.

Someone has to know something?

Sorry for sounding like a @$$, but i need some help.[/quote:530865ffdd]
Ok, well no answer.. Meh.
Jul 6, 2006 at 2:09 PM
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DODGER
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1000 RPMs is about normal for an idle speed. I have a '97 firebird myself and it starts out at 1200 RPMs and then drops down to a steady 1000.
Nov 9, 2006 at 4:32 AM
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GAMSO
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um adjust your throttle that will control your idle thats what i did....
Dec 7, 2008 at 3:21 PM
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JDL
  • ✓Experienced Mechanic
  • 16,098 POSTS
How long since a tune-up? Any applicable trouble codes? Check the temp sensor. If this has a map sensor, but no maf, a vacuum leak can cause the idle to go high. The leak may seal after engine warms?
Nov 22, 2010 at 1:28 PM

Suggested Repair

Check for trouble codes and inspect the coolant temperature sensor. If the engine uses a MAP sensor and no MAF, look for a vacuum leak that may seal as the engine warms. Also confirm when the last tune-up was done.

Conversation Summary

The owner of a 1991 Firebird with a 305 reports a high idle above 1000 rpm at cold start that settles after several minutes, a possible idle miss, and harsh engagement into reverse or overdrive. Plug wires were replaced and the plugs looked new. One reply said about 1000 rpm can be normal and another suggested a throttle adjustment. The expert recommended checking codes, the temperature sensor, tune-up history, and a possible vacuum leak on a MAP-equipped engine that may seal after warm-up.

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