My engine has a rough idle when cold. It gets normal once at normal temp, but if I press the gas pedal it smells alot like unburned gas. Its a 1995 chevy TBI truck the engine is about a year old, it has headers, holley 670 tbi, spacer, knn filter, crane compu cam, electric fans, msd 6a, new plugs(gapped at.55) cap rotor, cables, o2 sensor. My gas milage is at 10 mpg in city. I always drive slow and it still remains the same. My check engine light does not come on, maybe it does not work, I dont know what cold be wrong? Is 10 the best I can get? I have seen many other trucks that get atleast 14 in city.