Ok guys I disconnected my negative battery terminal(98gs) because I wanted to get rid of my check engine light to see if it would come back on or not. The car had been running great with NO problems at all even though the light was on. So anyway I disconnected it and hooked it back up a few seconds later. When I started the car the engine light was off but now it's idling very low(around 200-300). Does anyone have any idea why or better yet how to fix it? Should I have left it disconnected for 30 minutes to reset the ECU? I hooked it back up immediately to avoid resetting the ECU since I have no idea what that means lol. I just know about that from searching. Someone please help!!!

PS-the car has not been driven since I did this, I just let it run in park.

 

Try disconnecting it for 10 minutes or so and then try again. From what you said, you just pulled it for a sec and put it back. That's not enough time for the car to completely reset. Sometimes doing it that briefly will throw things out of whack.

 

Ok thanks i'm gonna go try it now. Is it ok to leave it disconnected overnight or is that too long?

 

It's fine to leave it overnight. I've left mine off for two months before