yeah im thinking it might be fuel pressure, ill have that checked out, although mine doesn't seem to leak fuel, it doesn't have a gaseous smell and the only fluids i see under the car is water from the a/c, but its good to at least get it checked out
clayton - the papers said that they put new rear end lube and rear end fluid in it but idk if they used the wrong kind but i dont think that would decrease my mileage by about 6 or 7 mpg
Try this: disconnect the vacuum line going to the fuel rail pressure sensor and plug the vacuum line with a bolt or something. start the car and check to see if you can see or smell fuel coming from that sensor. Report back as soon as this is done.
The rear end fluid will not effect gas mileage under normal circumstances. I wouldn't even look into or waste time thinking about the rear end or the wreck. Unless your rear brakes are dragging, you would have notice that by now if they where (smell of brakes burning is a noticeable smell).