I did blow out the spray bar.... And every bolt was tight everywhere on the engine. But I didn't check the muffler side of things. The pressure outlet on the muffler may be gunked up a bit. Also I think the muffler gasket has seen better days. I wouldn't think a leak at the muffler gasket would do much but maybe I'm wrong. Hopefully I can get this sorted out soon because I have a tribute that is begging to be flown!