Engine Performance problem
2004 Mazda RX8 Manual 52000 miles
I have a 2004 Mazda RX8 6 speed manual transmission with a little over 52000 miles. The car did have a check engine light on, I took it to a mazda dealership and they said there were no problems, so they reset it. I am currently getting less than 200 miles to a tank, which is about 11 miles per gallon. I sometimes smell the burning of gas when I start my car. I have a brand new air filter and just replaced my spark plugs/wires/coils, as well as a recent oil change. I am desperately trying to find out why I am getting such bad gas mileage. I do not drive my car hard at all to make sure it wasn't me burning the gas. Can someone please tell me some reasons that will cause this like fuel filters, bad fuel line, o2 sensors, so I can take it to a mechanic to be tested?