So the temps finially got into the 40's around here and me 2000 ls1 has started acting up. only with a full exhaust and !air the idle drops to about 100rpm. all the lights go dim and she wants to stall.

possible sign of a bad battery??

 

Is the car throwing any DTCs?

 

no, this morning i got out and the car seemed fine, turned it to the run position, all the instrument lights came on, then turned it to start.... one click and the entire system was dead, no lights no nothing.

 

check your battery cables. i know this sounds dumb and basic, but that happened to me and I assumed the battery was dead. upon further inspection the negative cable wasnt tightened down all the way, but it was on the battery. I felt like a moron for calling my dad for a jump over that, but it had the same signs as youre showing. I even drove it around for a few days without touching the cable before it came too loose. hope its that simple for you.
[wow this is old, didnt realize that]