Pontiac

I k my car into the dealership, thinking it was still under warranty, because my check engine light came on. the dealership called and said it is because the evap canister is getting stuck open or closed and it triggered that light. they said that they can replace it for $315.00. my first question is do i really need to replace it and how does it affect the performance of my car (i live in fl and there is no emissions test here)? second, if i do get it replaced, is that a decent price or am i being ripped off?

You have an 8 year/80,000 mile warranty on the part (gm emissions warranty). if you are over on miles, you may still try to complain to get them to cover it. the first thing i would do is replace the gas cap, which is a common cause for that problem. have a garage reset the light and see how that goes. it sounds to me like they are trying to burn you.