is there a main mixture screw or just one for idle mixture cause i think my car is running too rich...well heres what happened maybe someone will know whats wrong....first my air pump belt came off the pulley and when i tried to tighten it i broke the bolt so i took the air pump off until i get the bolt out, and as i was taking it off i discovered that it wasnt hooked up to the ACV anyway. so i took it off and the next day when i started it up it didnt sound right so i waited till after it warmed up but nothing changed - it idles at the right speed but it sounds like crap, backfires excessivly, and stalls easily when idling. its jumpy when coasting to a stop and when i hold the gas pedal in a constant position it doesnt accel smoothly, its jumpy as well. im still learning but it sounds like its running to rich but it doesnt make any sense - it started after i took the air pump off, but it wasnt hooked up in the first place! any info will help. thanks.