Ever since I have installed my cam, longtube headers, and underdrive pullies, I have had terrible gas mileage. I mean I do drive it kinda hard but I am getting around 10 mpg. Is this right or is there maybe something wrong with my tune or could it have to do with the O2 sensor prob with running no cats?

 

is your car tuned?!? that will be one factor. and what did you expect when you threw all those things on lol. your gonna have some loss in gas mileage, and since you drive her hard to that helps as well. try not gettin on it for a tank and see what happens

 

You're more than likely running rich, and the heavy foot doesn't help the situation. Its time for a tune bud..

 

If not, go get tuned. If so, go get a retune...