Try filling up with premium instead of regular. That usually yields a 10% improvement for me. Plus, the car feels gutsier off the line.
Engine braking heading toward stoplights and on downgrades - is that possible for the automatic? Try that if you can. As long as the downshift doesn't send the engine beyond the 3500-4000 rpm range it should yield some quite amazing results. (Fuel injection shuts off.
) (FYI - I feel uncomfortable with engine braking above 4000. It just sounds too brutal.
)