Battery light comes on and off

Nine times out of ten when battery light comes on alternator is bad

You need to find the cause of the idle fluctuating. If the idle is going so slow that it almost dies, that could cause the battery light to sometimes illuminate. My guess is that the check engine light has something to do with it. Get the trouble codes read and do some research as to what problems are associated with your trouble codes.

Thanks i will get a code reader tomorrow and see what it says for codes. I unhooked the battery while it was running and it died right out. Think I need a new alternator? Right?

Never unhook a battery when the engine is running. The voltage spike can sometimes damage the ECU. Have the battery and alternator tested.

Will do that this afternoon after work.

Fluctuating idle could be dirty throttle body and IAC. Video on the net will show how to clean.

Check for carbon build up at the throttle plate in the throttle body. You can buy spray cleaner for it and watch a vid on how to do it, as the other gentlemansuggested.