Pontiac Repair: hesitating while idling, crank shaft, maf sensor

Question
Hi Todd,
I got a 96 Bonneville with around 190,000km on it. Out of the blue the car started to hesitate while i was driving (rpm knocks from x to 0 then backup again repeatedly)  then the engine light comes on. At a stop or red light it hesitates and the voltage drops to battery power causing it to occasionally stall. Sometimes when i start her up the engine light is off until she randomly starts hesitating again.
This just currently happened during our winter season. Just curious which sensor could be causing this because i replaced the MAF, IAC, battery, & the TPS, plus the grounds in the engine bay where cleaned. The alternator is almost toast so that needs to be replaced but i dont think thats causing the hesitation and the engine light.

Thanks for your help,
Syl

Answer
Hey Sylvester:

well first off fis the charging system. if the volatge is dropping out it will cause all kinds of issues. How does this strat when it's hot? does it labor spit and run rough? does it billow black smoke? Did you replace all these parts with original equipment parts? especially the MAF sensor... I realy am not a fan of aftermarket parts expecially electrical parts!!! I think I would look at possably a fuel pump issue and or a ground for the fuel pump or possably a crank shaft sensor.. if you can get this to act up just running in park that would help out. Put a fuel pressue gauge on it and see what happens when the car stalls and see if it looses fuel pressure.If not then it's not a fuel pressure issue. it could be either a fuel delivery issue or a spark issue... just trying to anrrow it down is the big thing...
Good luck :)