...stumbling and misfiring? Hey I rencently blew out a radiator hose and my car overheated and smoke started coming out. I replaced the hose, replaced two (FRONT//BACK) gaskets on the engine, im not sure what exactly they were called. I thought it was the main head gasket, but the car would be undrivable. It was overheating but i flushed the radiators and cooling systems it seems to have fixed that problem. the engine is now stumbling a LOT and it makes a whiny, misfiring sound now. anyone got ideas? maybe fuel system? intake manifold? it seems to idle poorly and have trouble keeping RPM up, but when your driving it shakes and vibrates less.