I recently just changed the following: 2 front tires, fuel filter, spark plugs, wires, a fuel pressure regulator, and 2 oxygen sensors. Before the install, I was getting a terrible gas smell and an extremely rough idle. The problems have been fixed, but I still only get about 200-250 miles to a full tank mainly highway with cruise set at 60-65. Is there anything else that could possibly cause this? I saw on a previous post that one guy's brakes seemed like they were rubbing or something like that. Now that I think about it, at low speeds there is a slight squeal from the breaks even if I dont hit the pedal...could this small amount of resistance be causing my mileage problem? thanks