I get high mileage (33) even though I have AWD. The weight of the drive shaft and attachments for 4WD (300 lbs.) is the only consideration when not using 4WD and it subtracts about 1 MPG. When actually using 4WD (off-road, snow, and weather) you will lose about 10% mileage.

The downside is that there are some conditions of high loss of torque (the wheel or wheels are stationary and the engine starts to increase power input but for some reason cannot overcome the torque required to move forward) the engine will get to a certain point (as directed by the software) where it will decide to start shutting down power output so as to not hurt the engine. The software in the original is too conservative and there are reports of vehicles coming to a stop or not being able to pull itself onto pavement. This has happened to me. It may have been fixed in firmware updates. The self-fix is to reboot (turn off the car and turn back on) and every bit of power comes back. I hope this is understandable.

Mike

Mike Maline - Sdctcher
2005 Ford Escape Hybrid Owner
California School Teacher