I finally got past the 14mpg mark with my X5 4.6! I calculated 14.2mpg at my last fill up (calculated at the pump, not the OBC number). This is with driving it pretty gently and not racing anybody. My commute is still mostly traffic though, so I can't see it getting much better than this. I get about 300 miles out of a gas tank before the gas light comes on.

I recently rebuilt the chain guides + vanos + OSV, as well as installed new spark plugs and a new engine air filter. I'm wondering if getting a new MAF and new O2 sensors would increase my gas mileage— I have 214k miles as of now, no idea whether the MAF or O2's have ever been replaced.

__________________
2003 X5 4.6 | 2000 540i Touring

Formerly owned:
2004 Range Rover | 2000 M5 | 2000 540i/6
1995 750il | 2003 Mercedes S500 | 2003 540i/6