idle problem

[AA02gt]

i just got a 2002 mustang gt. i am having problems with the car idleing.... my car idles around 750ish, but i found that when i have my defrost/heater on, the car idle kicks up to around 1250 for a few seconds and kicks back down.. this repeats over and over, anyone know whats up? Thanks

 

[Red2000GT]

When the A/C compressor kicks in and out it will cause the idle to jump. Normally the computer can adjust so there's not much fluctuation but are there any mods to the car? ALso,does the A/C system work?

 

[Red2000GT]

I guess i should explain that the car uses the A/C compressor to de-humidify the air when using the defrost and that helps clear the windshield faster.

 

[AA02gt]

oh thanks for the info... my car only has exhaust so. it sounds like it is sapost to do that then???

 

[AA02gt]

oh and the ac works too...

 

[bluextc]

http://forums.stangnet.com/showthread.php?t=669621&highlight=iac

 

[Red2000GT]

oh thanks for the info... my car only has exhaust so. it sounds like it is sapost to do that then???

A little fluctuation is normal but not that much,and the compressor shouldn't cycle on and off that often. I'd say you're running low on refrigerant.

 

[Jsun3701]

I have the same year GT. Check the belt make sure its got good tension. Then I would clean the IAC, its cheap and doesnt hurt , just helps. I hate to be one of those people but try the Seafoam, its a champ man. Cleaned my idle right up.