Idle gets Higher when stopped

Alright, I have been having a lot of problems with my car since i put that header on, But this is the worst of all of them. Last night i put a brand new alternator on. I was thinking this was going to fix my problems with the battery light. Well it didnt. When i drove my cavalier around last night i noticed that the battery light never went off. I drove about 100 miles and it didnt turn off once. I didnt think a lot about it. But today was the worst problem i have had to date. I was driving alone and it was starting to sputter like usual, but i didnt think a lot about that either. After that i was driving down the road and then i saw my check engine light come on and my ABS light came on too. When i stopped at a stop light my buddy and I looked at eachother and we were wondering why my car was not going into idle, what we noticed every timw we stopped at a stop light was that the car was idling at about 1500 - 2000 and it was getting higher. Then like 10 minutes later my car started tweakin like when my alternator died on me. Now im starting to think that my alternator didnt die. then i live in a neighborhood and its a slow speed limit and i usually go about 10 - 15 MPH and today i couldnt get less the 25, i slowed down to about 15 MPH and my idle just kept speeding my car up till it was about up to about 26. I dont know whats wrong and im starting to think that I need to get rid or my car. Its having to much problems to even deal with anymore. Anyone know whats going on?

well when that happen in my camaro the idle screw came all the way out. but i dont know if these cars have a thing like the camaro has.

i dont think that the camaro will have the same idle screw as a cavalier. probably your camaro was carburated i got fuel injected. probably has something to do with the computer. but i have no clue

I am having this exact same problem. I own a stock Cavalier, at first it was just my check battery light then my ABS then the idle thing. My Air Bag and Brake lights came on as well. Please someone figure this out for us!