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Discussion Starter #1
When I start my car the rpms go way to high. It only does it when it is cold outside. After I get almost to work which is about 15-20 minutes I can depress the brake really hard and it goes down. I carried it to the GM dealership and of course they did not find anything wrong. But they still charged me. I need help!!!! Please E-mail or respond
Thanks
 

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Is it fuel inj or carburated? Need more info.Carbs have a fast idle screw that is on the passenger side that can be adjusted. This is the choke idle speed screw.

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68 RS, Ash Gold,pwr windows,Hounds tooth
 

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I think most of all fuel injected cars have a idle air control. If the car has some mileage, they get like stuck either open or closed. Maybe take a look at that and spray some carb cleaner to clean it up or maybe replace it.
 

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my 90 rs had the same problem, but only when cold. i had problems with the wiring harness that went to the tps switch (3 prong plug).
i went to gm, bought a kit, and replaced it and that solved my problem.
here the wires got corroded and broke loose to the pins inside the plug and would cause a bad connection.
cost me 23.00 bucks and haven't had the problem since.
bruce
 

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Discussion Starter #7
I called my local GM dealership and they told me I would have to buy the whole engine wiring harness. They said I would cost me about $500.00. That is a little too much for me.
 

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Discussion Starter #8
Its getting colder and I need to fix this kind of fast. Any help is greatly appreciated. Bruce69camaro get back with me and let me know what I can try. Thanks
 

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I used to have an 83 mustang and i put a brand new double pump carb, and when it got cold out here in california, it would do the same thing, start it up in the morning, and it would jump to around 2000 rpm, then settle down, maybe the problem isnt in your fuel injection??? just a thought
 

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Only two things affect idle rpm - the TPS switch tells the computer whether or not your foot is on the accelerator past idle position (and how far), and the Idle Air Control motor opens, modulates, and closes an air passage into the manifold during idle when the throttle plate is closed to manage idle under varying load conditions. One of these two devices (or their electrical connections) is causing your problem, assuming your engine computer is working and its electrical connections are good.

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JohnZ
'69 Z28 Fathom Green
 

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First thing would be to take a real close look for a vacuum leak. Then suspect a worn throttle body. You would need to scan the computer and check the IAC counts. Normal might be about 17, with a leak somewhere you might be seeing much less or even zero. Could possibly have an out of spec temp sensor telling the computer it is 30 below zero too. A dirty connection could cause this. Again a scanner will pinpoint this real quick. Check for vacuum leaks first. Check throttle body bolts.
 

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Discussion Starter #12
I tried taking it to the dealership and they checked it and said they could not find anything wrong. What do I need to do???
 

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Beaver, if it is throttle body injected the base gaskets do give a problem. You could do a key on engine off check and listen to see if the IAC motor is at least working, you should hear it clicking trying close. Then again its hard to believe a dealer didn't try any of this.
 

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sorry i took so long to reply back, but i went in and asked for a repair kit, for this plug, and they gave what what i asked for. i beleive pep boys might also have a repair kit for this plug. if i remember correctly, they call it a gm weathertite plug kit, for this tps switch. but ever since i replaced mine, my car has worked fine. in the mornings, when it was cold, i'd go out and start it and the rpm's would go high, until i would try and drive it, then after the car got a little warm, it work then work. but after i would let it sit, the same thing. i try and drive it and it would spit and putt around and bearly move. then after it got a little warm, it would be ok.
the harness kit had the plug end with three wires about 8 to 10 inches long and came with crimpable wire ends. it has a gm part number, but i threw out the bag it came in.
bruce
 

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Beaver, if it is throttle body fuel injected, try this, with the engine running, spray some carb cleaner around the base of the throttle body and if the idle comes back to normal, the problem is the base gasket under the throttle body. I had this happen to a friends truck and by replacing the gasket, all is well. Hope this helps.

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Leo Paugh
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There are no strangers here, only friends you haven't met.
 

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Discussion Starter #16
I checked the tps switch and it was not in bad shape. It was not corroded. I will check the throttle body gaskett tonight.
Any help is greatly appreciatted.
 

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The only two things it could be is your tps voltage is too high or your someone tried to adjust the minimum idle screw thinking it controlled the idle. If someone adjusted the minimum idle screw your tps voltage will also change.
 

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<BLOCKQUOTE>quote:</font><HR>Originally posted by bigtedards:
I used to have an 83 mustang and i put a brand new double pump carb, and when it got cold out here in california, it would do the same thing, start it up in the morning, and it would jump to around 2000 rpm, then settle down, maybe the problem isnt in your fuel injection??? just a thought<HR></BLOCKQUOTE>

Please don't say that "M" word around me again ok? It makes me wnt to throw up.
 
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