89 lxi with some wierd idle problems

[tysn]

my car idles normal till i turn on the heater, then the idle bounces from 700 to about 1600 rpm and back and forth again. it continues to do this til i turn off the heater then it goes back to normal. any idea why it does that?

[kcaudill]

Dont turn on the heater

[aerokid1987]

Dont turn on the heater
What a worthless comment:huh:

I am not all that familiar with the heating and cooling systems in our cars but i have one question, how fast does the idle speed change?

[tysn]

it changes idle speed like very second, its pretty quick

[Accordaone]

my car idles normal till i turn on the heater, then the idle bounces from 700 to about 1600 rpm and back and forth again. it continues to do this til i turn off the heater then it goes back to normal. any idea why it does that?
I would check the level and bleed the air from the coolant. The 3G's idle is real sensitive to low or air in the coolant. The heater may be taking some of the coolant and leaving air on one of the thermistors. Good luck.

[TdotWarrior]

hey i got a 87 lx n when i start my car n it idles it USE to go from like 2100 to 1300 n keep goin up n down but all i did was screw in sum screw near the top of the engine cuz it keeps coming loose so now i screwed it in pretty good n it will only rev at 900 or how ever i want it ...... ill get you a picture of where it is in a day or two