hey whats up guys, what causes a car to idle funny when you turn the defrost on......my car idles normally around 900-1000, but when i turn my defrost on, it goes to like 400, then goes up to about 1500 without my foot being on the gas....[&:]

 

the only thing i can think of is a surge drawing power at a sudden spike then your computer compensating for it

 

Yeah, mine does that also. It doesnt revt hat low or high, but it does surge for abit.

Everycar is different, maybe yours just does that for what ever reason. Could try cleaning the throttle body.

 

our auto. Neon does the same...but only by like +/- 200rpms.

 

When you turn on the defroster, it utilizes the A/C, thus creating more drag on the engine, then engine then compensates for that by giving a bit more gas.

 

so i guess its nothing i really need to worry about huh...

 

It's quite noticeable on cars with weaker engines, like Geo Metros.[&:]

 

mine had a idle problem too.

after the car got warmed up (driving it for about 15-20 minutes.) I would be driving around 2500 or 3000 rpms, and the car would jerk really bad and if i push in the clutch to the rpms would drop to around 400-500. normally the car would die at such low rpms, but it would try to rev itself back up, if i would push the gas its like the gas pedal didnt work anymore, it would do nothing, once it caught and reved up it would hold the rev at 4500-6000 rpms consitally, thats without me pushing the gas.

so long story short i needed a new crank sensor and pigtail, cam sensor and pigtail, and upstream o2 sensor.

problems fixed now though