power in my car keep going in and out
This happens in a lot of older cars......90% of time I find it is a loose battery cable......or a torn battery cable. Check those out.....if you can move it or it is dirty...then clean and//or replace
Could also be a bad defective body control module
More likely than not, it's your body control module. It's located under/behind the glove box. Why this happens is that it was a bad design, and the soldering is shoddy on the circuit board. You need to remove it and re-solder it. There is a tutorial somewhere here on how to do that, or you could search the web for body control module repair. Good luck! I've had to do this twice in the 7 years I've owned my 'Bird. Buying a new bcm is dicey, since it likely won't be the same resistance as your old one, and you'd have to go to the dealership to get them to reset the computer.
Looking for a Used Firebird in your area?
CarGurus has 762 nationwide Firebird listings starting at $3,800.
Search Pontiac Firebird Questions
Pontiac Firebird Experts