I have a Merc 888 with a 4bbl Holley installed. After the engine is warmed up, if I go from a cruising speed to idle, the rpms will start to fluctuate back and forth from about 100 to 1000 about four or five times until the engine dies. Once it starts doing this, I cant put it into gear at idle speed without it dying again. To start it back up, I have to pump the gas until it fires, revi it up for a couple of secs. and then go. It also will hesitate during acceleration and sometimes backfire if I gun the throttle. Any ideas?
