I have gone through 2 tanks of gas and my mpg has been between 15-16 mpg. The car runs great and the check engine light has not been on in quite some time. Yes, I cleaned my MAF sensor and reset the comp. I have not added any mods recently. I have noticed my Flowmaster mufflers are rusting out a little though. Do you think that my exhaust could cause the terrible gas mileage? It seems to me it could be part of the problem but to drop me down 6-8 mpg?!?!? Any help would be appreciated.