Ok a couple of weeks back i noticed that my gas mileage was dropping and that my car was throwing alot os smoke.. So I changed my spark plugs, cables, also cleaned my injectors (I paid it so they could do it), and I cleaned my k&n cone. My mileage has improved a little bit but the smoke doesn't go away. When the car is in a stop and I step normally on the gas pedal, smoke comes out, It does that every time... What can I do to get rid of the smoke????