I got and 07 Grand Prix and it is starting hard. It only starts hard after it has been sitting like after work or over night. It rolls over a lot then starts or it rolls over a lot then i turn it off and it starts right off again. I am supposed to run premium as i have a super charger. I changed my fuel to the mid grade and it starts better or even hardly ever starts hard. I switched back to premium and the same thing. So i put the mid grade back in it. What does this sound like. The gm garage told me it sounds like a fuel pump and it shouldn't matter that gas i put in it and that it is basically nothing to do with fuel kinds.
Thanks please respond with ideas.
Would hate to pay someone 100s of dollars to tell me its some sensor or something in that nature that i can do myself..
