my crx is popping when i'm in gear and let off the gas and my rpms are at around 3 to 4 grand, and yes i smell gas in my exhaust. cough cough. also not much, but when i get on the gas black smoke comes out of the exhaust. well... i guess a bunch cuz the entire back of my car has like soot on it, and i wash it ever 3 days and it gets covered in soot in that amount of time. how can i learn why it's running rich?