My rpm in my car goes up and down really quickly when i am coming up to a stop light and then sometimes it dies. now i think that it is something to do with the battery and i know that there is a trick to fixing it but i can't remember. the trick that i have heard of i to unplug the battery and then let it set then replug it in but i don't remember for how long or if that is right.

SOURCE: battery not charging

Sounds like the cells in the battery have shorted. It's probably shot. Does the car run once its jump started? Does it continue to run after the cables are removed, if so your alternator is ok and its the battery. Hope that helps.

SOURCE: replaced alternator and battery still showing low/varying voltage

It soundls like you have a high powered sound system and you might have to step up to a higher amp alternator, that will give you enough power. Your battery should be fine too. Try to find out if the voltage regulator is built into the alternator and if not ask to find out where it is on the car and replace that to.

SOURCE: Oldsmobile Draining Battery

You will need to check for battery voltage at the back of the alternator. The larger red wire.

SOURCE: 2004 Olds Alero with constant high RPM

Try cleaning the throttle body. Possible idle air control valve problem.

SOURCE: Idle problem with an Oldsmobile

try to get the light to come back on and find out what the code is at a local autozone for free. the code will helpfind the problem