Hey my '03 Sentra SE-R seem to have been losing gas mileage. Before it started getting cold and before I got a new cat-back for it, by the time I get to the last quarter on the gas meter, it would have ran 270miles. But now by the time it gets to the last quarter, it only ran about 220. Could this be a cause of cold weather or is there something wrong? If it's just cold weather, could someone tell me how I could fix this? Thank you.

the exhaust makes you get less mpg, but the cold air should help gain mpg..

the exhaust makes you get less mpg, but the cold air should help gain mpg..

Hi, thanks for the comment but do you think you can explain to me more in depth why each one would make you lose and gain mpg? cuz i thought that the cold air would make you lose mpg because denser air would mean mixing with more fuel wouldn't it? And with just the winter air and the exhaust, would I really lose that much mpg?

well it should be a minimum difference. but i do know the exhaust will make you loose bout 4mpg, and the intake should make you loose just a bit if your air-fuel theory is right. dot worry,you shouldnt see a big diff anyway in your mpg change.