So, the car sat in the garage for a few days while it was snowing outside and now it doesn't run. Gives me a Code 51 PROM error and will barely start and miss horribly. I think it's running off the limp tune.

So I put in another PROM I had and it did the same thing. So I even burned a tune 1 step back that I know ran. Same thing. Think the ECM is shot?