i'm getting all sorts of random idle speeds on any given day, anywhere from 750 to 1900 when I first start it up. typically it sits around 1600 and won't drop til i drive it around a bit, then finishes from 800-1200. is it possible for the throttle to stick a bit from time to time? at times it acts as if you're pressing the pedal, which i think results in my occassional high idle..

anyway. the point is i'm getting really bad fuel economy (or sure feels like it), my exhaust smells terrible (worse than your typical exhaust haha) and i'm backfiring quite a bit when shifting from revs over 4000 even when the engine is warm. is that what you'd call running rich? <noob> if so... is S-AFC the only real way to fix it up? or... replacing the O2 sensor? i did a quick search, but since i dont know much i didnt really learn much :S