turned the car over and engine started. it will run for around 4 minutes and the car will shut itself down but, will restart as you turn the key over. thinking its a vacuum problem but can't figure it out. the alternator was changed, along with the battery and starter and fuel pump. thinking that i might to change out the fuel filter? or maybe even the fuel pressure regulator. I need help badly! if you have experienced this problem before, please tell me what to do.and i cant find the pressure release valve on my motor, where is it located? in dire need of help!