Rough Idle Causes? Options

[Nano]

What could cause the car to idle roughly when not moving but in gear? When its still but in gear ( Ie: Redlight ), it vibrates rather roughly, when its in park its fine, and when its moving its fine. It also on occasion has sharp drops in rpms ( around the 300 mark ) over and over again, typically when running the AC. Anyone have any idea what could be causing this?

This post has been edited by Nano: Apr 19, 2006 - 2:18 PM

[95CelicaST]

Do you have an Auto? Manual? Have you unhooked the battery recently?

I ask because when you unhook the battery the ECU resets. When you hook it back up you need to let it sit and go through the re-learn process, or it will drive like crap. I did this a while back and went through a tank of gas in a day. not fun.

[Nano]

[quote name='95CelicaST' date='Apr 19, 2006 - 2:39 PM' post='423580']
Do you have an Auto? Manual? Have you unhooked the battery recently?[/quote]

Auto, yes... sorta anyway. I bought it two weeks ago, it had a non spec battery on it, and it ran like that then. As of yesterday, i replaced the non spec battery, since the other died. :\

[qoute]
I ask because when you unhook the battery the ECU resets. When you hook it back up you need to let it sit and go through the re-learn process, or it will drive like crap. I did this a while back and went through a tank of gas in a day. not fun.
[/quote]

How do you do that, exactly?