Hi I've noticed that when sitting idle and if I turn on the a/c my RPM actually goes up a little bit. Nothing too high or anything just to the 1 mark or lower. What could this be?? Cars a 2000 cherokee sport

 

Completely normal.

 

Normal.

All cars do this. The AC is a pretty big drag, so the computer kicks the idle up slightly.

 

ahh ok. Just wanted to make sure it wasn't a problem. Thanks!

 

I believe the IAC (idle air controller) kicks up the idle when it senses a load. If it's set perfectly the idle should stay the same. Yours may be dirty and it can be cleaned. Engines with carbs used a vacuum controlled system called a dashpot to maintain the ide speed with the A/C on.

 

Mine goes down ans stay down.... would that mean that IAC is not working properly ?

 

That would be my first guess. It's not too hard to clean from what I've read. I just replaced mine. There's a lot of IAC posts here...do some searching before you start throwing money at it.