454 Back fire thru exhaust
I have an 88 Gulf Stream Sunsport that I recently bought. It has been sitting for 2 years and it runs good except at about 50 to 55mph it back fires thru the exhaust. E have changed plugs and wires an...
Forum Discussion
Does your truck have an air pump as part of the emmisions system? A bad diverter valve and or check valves on the air manifold will cause this. This is a 1988 and it still has a carb? Most of GM trucks switched to throttle body injection in 1987.
