I need to start using fuelly but migration from fuelio would likely take forever. Have to see if there is an export function...

24mpg is an outlier (we don't manage that with our 2015 diesel @23.76mpg, lol), but the rest look in line with ratings. Looked up the 530xi wagons and they are similar to the X5 ~17-18mpg for the 6HP autos. We've managed 19.34mpg over 8850 miles with a best of 22.42 on a road trip. Not a fan of the N52 for power or economy, but it is a smooth engine and really enjoy it in the wagon. That said, I have a 550i parked outside that is a donor drivetrain for the wagon. Can't wait to have N62 powered RWD wagon over N52 AWD wagon. After this discussion I can't wait to see how MPGs change.

Anyway, enough back and forth. OP, do you have any codes or anything? Let's have more info on your drive cycle and such. Hilly/mountainous highways? History of the vehicle?

When I first rescued our wagon from its fate going to the junkyard @ 185k miles I was sure to do plugs and coils and run cleaner through the fuel system before starting to drive it. Also did trans, diffs, and transfer case fluids. Maybe you could eek out another mpg or so with some maintenance items?

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2005 X5 4.4i Build 04/05 Maintenance/Build Log
Nav, Pano, Sport (Purchased 06/14 w/ 109,000 miles) (Sold 8/15 w/121,000 miles)

2006 X5 4.8is Build 11/05 Maintenance/Build Log
Nav, DSP, Pano, Running Boards, OEM Tow Hitch, Cold Weather Pckg (Purchased 08/15 w/ 90,500 miles)

2010 X5 35d Build 02/10
Nav, HiFi, 6 DVD, Sports Pckg, Cold Weather Pckg, HUD, CAS, Running Boards, Leather Dash, PDC, Pano (Purchased 03/17 w/ 136,120 miles)