total loss!!!!!

why is gas seeping from my valve cover? I replaced the pressure regulator,the fuel filter,the injectors,the oil and oil filter from contamination,and the spark plugs and it still spits out the seam of the valve cover on the back right side facing the motor. The car sat for three months while I was in Florida and before I left I gave it a complete tune up and she ran like a champ. I never drove the car hard or a lot so I cant think of it being anything serious because it just sat untouched..dead battery I understand but this has me stumped...too much pressure building in my crankcase?...no idea. Help please!!!!!!