a couple of weeks ago going too a cruisin. all of a sudden at a stop light my motor shut down. my fuel pump went out. i have a inline clear glass filter before the pump. and the pump has the canister type filter on top. i put a new pump on and got it running . but their is a mur-mur or skip . my tach is bouncing 200 rpm between at choke high idle,an at regular idle. before the tach was so even-steven. my spark plugs are not fouled and i changed my wires. my mechanic did the once over on the carb but it is till there . do you know what it could be?