[royalty24]

so i originally i had terribly leaky valve cover gaskets on my 90 f150 i pulled off the upper intake to get at the passenger side bank (god bless whatever engineer designed the 5.0 upper manifold) anyways needless to say i replaced both valve cover gaskets with some felpros from the local auto store i also picked up a felpro manifold gasket set to replaced the upper one. also picked up a new EGR gasket for good measure. Well after putting everything back together i had a terrible intake leak and it was running like ***** with a huge sucking noise. so i pulled off the upper again and siliconed the gasket. still same problem. went back to auto store and bought new felpro gasket set and was a bit more liberal in my use of silicone. so i fire up after waiting a 24hr period to let the silicone dry i dont hear anymore vacuum leaks however whenever its at low idle it sounds like its about to die. Also it will die when sitting at a stop sign but fires right back up again i sprayed carb cleaner around the base of the manifold and it doesnt bog down or anthing i also replaced plugs an wires and the same time when i had the upper manifold off. All vacuum lines are plugged in nothing isnt where it was when i started the repair. needless to say im outta ideas.. HELP?