Have you tried adjusting the maf sensor? my car had the same problem. i use the get 15 miles per gallon, and would not even come close to passing smog. then i adjusted the maf sensor, and my car went from 14.7 to .004 emitions, and is now getting 20 miles per gallon. there are forums here on how to do it. but if you don't know what you are doing you might want to pay a mechanic to do it. the best way is to take it to a smog place and hook up their machine in your tail pipe. Then adjust the sensor. this way you know were to leave the setting. if you do it with out the the machine at the smog shop you could make your car to lean and hurt your engine.