Have 2000 ws6 cam only with bolt ons deleted pcv and put rpm transmission in a once i got it back it started sputtering. Like when i t get to 4000 it starts cutten out then it go away for sec then come back. When it sits still sometimes it will pop. The car is slow *** **** now. Ive changed mass air fuel filter plugs wires i don't knw what else to check please help asap.