[MetroMPG]

Another unrelated thought: obviously your XFi's wheels are aftermarket. If you haven't already calculated the difference in circumference (affecting your speed/odometer), you'll need to apply a correction factor to get accurate fuel economy figures.

AND - even if the engine is due for a rebuild, for the price you paid, it's likely worth it if you can do the work yourself. A rust-free Cali XFi is worth the trouble!