I'm thinking I need to give my 304 a tuneup. It's running a bit rough, it likes to backfire and pop whenever I slow down or let off the gas. If I don't 2 pedal it it likes to stall at idle. What causes this? I've got a 304 with a mild RV cam, hi flow water pump, stock everything else and 2100 carb. The carb had a rebuild kit go in it just after Christmas time by a fellow who knows his way around one (I don't). He also adjusted the 2 screws at the base of the carb. I'm told you turn them all the way in, back them out 2.5 turns and start tuning from there. He had to turn them 9 turns to get them all the way in so I'm thinking they might have backed off again?