My 2004 RX8, Automatic Transmission is getting HORRIBLE gas mileage. I noticed every so often the engine light blinks, i pulled the code and the engine misfires. I am getting around 11-12mpg constantly highway or city. Any thoughts? I know in the 53000 miles its been around, it hasnt had coils plugs or wires replaced except once when it had about 6000 miles on it, when the recall was issued. Time for a tune up?