I have been having horrible vibrations from under the trunk area, so bad i cant even drive the thing. so i took a peek and it looked like one of my hose clamps on top of the pump was hitting the underside of the trunk. i dropped the tank just to move the clamp so it was out of the way, and the vibration is still there! nothing is hitting anywhere back there. question is, can a fuel pump vibrate and cause this? the car is not holding pressure after shutting the car off and from the diagnosis i used on gnttype.org it led to bad fuel pump check valve (not holding pressure) can this cause vibrating or am i missing something?