I dont know if anybody has ever had a problem with mpg. im curently avg. between 11-13 mpg . i took it to professional muffler because this all happen right after i got my new magnaflow exhaust on and they said it was the catalytic convertor and i just got that done yesterday and doesnt seem to be a big help atill getting only 13mpg. but first i took it to auto zone and they told me a 02 sensor but then prof. muffler told me the catalyic convertor. so someone help plzzzzz!!!!