It seems to be building up pressure in the engine it will start but runs rough if i keep it above 2000 rpm it seems fine butt when it runs it will make a poof sound and smoke comes out of the PVC valve coming out of the valve cover and its so bad that the oil dip stick flew out from the pressure and i thought the problem was the catalytic converter being clogged but i disconnected it to see if that was the problem and it is not so i dont know what to do or try