So we have a 2002 Pontiac Sunfire, 2.2 litre. Bought the car, used it not even 24 hours later the battery light came on, did a multimeter test, showed the alternator was bad, bought a new one and changed. Worked good for approx a week. Now the battery light comes on and off. When the battery light is on, the wipers are slow, the stereo quits working, when idling the rpm's will drop down and before stalling jump back up, all the lights on the dash will light up (battery, abs, e-brake, airbag etc.), the speedometer and tachometer will quit working also. ANY IDEA WHAT THIS COULD BE???

Ya we will try that, if the alternator is bad, will it cause it to do all those whacky things though?

that and a new battery as well .

Yes alternator...i bought 3 brand new alt's and none were good...they all overcharged and so i got a used alt from a wrecked car that was running fine until it got into an accident...finally worked. This took approx 1 month...i know it sounds backwards using a used alternator but all the brand new ones are no good...learn from my experience...i had to drive 120 miles a day in a V8 truck the gas alone i could have bought a small car...get a used alternator from a wrecking yard...dealer sold me 3 and had my car for a month...