Mechanics

ENGINE IDLE PROBLEM AND AC PROBLEM

2002 Pontiac Sunfire

Engine Performance problem
2002 Pontiac Sunfire 4 cyl Two Wheel Drive Automatic 99000 miles

Hello there,

I am by no means good with cars, but I know slightly more than the average female and sad to say way more than my husband.

We recently got a 2002 sunfire that had to have the fuel system flushed and fuel pump/module replaced do to vandalisim.

I bought it knowing this and I was told that it ran fine before hand. So when I start it up it runs fine idle wise with the AC on, but it sits around 500 RPM. Well as soon as you touch the gas the idle sitting still gets rough. It jumps from 500 to 300 and then like 500 to 200 and each time going lower and lower until it cuts off, but only when the AC is on, But if I cut the AC off at the light (or where ever) it still jumps on the idle but not that much, hardly noticable but you can feel it. If you know its there.

I have had the fuel filter and oil filter air filter and oil changed. Is it perhaps the plugs that need cahnging/cleaning?

ALSO, I think there is more to the AC thing because the AC cycles cool warm cold, cool warm cold, and only cool and warm when sitting, only cold while driving and for about 1 min at a time. So this leaves me to believe that I have some issues to work out. Oh yeas I also checked the AC and the coolant (R 134a?) Is fine, I used one of the Valves you get from walmart, it sits right on the line of green (coolant fine) and Yellow (seek mechanical attention does not need coolant).

Is this a problem that I could perhaps work out on my own, using guides and extensive information and research? I have access to machines tools garage and computer diagnostics on the military base. I do not know where much is on this car, more familure with fords, but I know basic terms.

Thank you in advance for your help!

Jennifer


thank you, but where is the idle air control valve ocated at? Thank you
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Jluthye
July 25, 2008.



Check the idle air control valve and hope that's it, otherwise the pcm which boosts idle when the a/c is on may be going, but the main culprit is usually found to be the IAC. As for the a/c, if you want to try and figure that out, buy a good set of manifold gauges, knowing only what a cheap gauge low side gauge reads is telling you nothing! You also want the high side reading to diagnose problems.
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Merlin2021
Jul 26, 2008.
I just fixed my problem of car hunting up and down and lurching forward at red lights when a/c is on. I spent about a thousand dollares looking for my solution. No code came up, but having been a mechanic I went for the Idle Air control motor. Then the throttle position sensor. Ran better but no cigar. After two years of chasing this I found the problem. The plug(3 wires) on the a/c compressor on the high side sensor. The wires on the plug are very small and were cracked and were not letting the voltage needed to run things correctly.I guess it worked intermittently thru vibration of engine.A new pigtail(connector) GM part # 88988301. At a cost of $103.43 Cdn fixed this and it runs perfectly.I hope this helps cause I was running out of patience trying to repair this problem on my wifes car Sometimes its bettewr to have extra help to fix a problem. If this works for anyone reading this pls email me to let me know at dfensom@telus. Net I only signed up here in hopes of helping someone fix the same frustrating problem so I hope it helps. Pls email. Thanks and good luck

Tiny
Bigdon
Jul 21, 2011.
I was having a similiar problem with my a/c in my 2001 Sunfire and after a few months of trying to eliminate the problem my brother went out to my car because he heard a horrible noise. Well, the noise was my tensioner pulley going out and he figured since he was already under the hood he would check out a few things with my air. He noticed my fan was not turning at all and he looked at a few possibilities before he tapped my relay switch and BAM. The a/c works again, my car no longer idles high, and I can stop at a redlight/stop sign without being******* forward. Such a simple fix, so I suggest tapping your relay switch before spending thousands of dollars.

Tiny
Mrsthibodeaux
Jul 29, 2011.
Bigdon and mrthibodeaux, thanks for your replies.

Jluthye, did either of these responses help you fix your problem?

Rivermikerat
Oct 5, 2011.

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