Okay I am working on my mother-in-laws car. Well the front end will start to shake when you are accelerating between 30 and 40 MPH. Sounds easy the motor mounts well not I have even changed out the transmission motor mount. Well that is one here is the real brain stopper. If you get in and start the car your gas gauge will read say half a tank well as you start rolling and you go lets say just 1 mile the gas gauge is now saying you have about 1/8th of a tank and you turn the car off and let the pump whirring noise stop and you start it back up and it is back at around half a tank. I am thinking the fuel pump is either starting to go out or the float device inside the pump is getting hung up. Any ideas?