Well, a couple of things:
1. Transmission plays a big role here. I had a Taco with the 3.4 and 5 speed and even though the Taco was longer and heavier than the 4runner, I got much better MPG than my '99 4runner. I blame the automatic tranny in the 4runner.
2. Just curious but have you checked your odometer to see how accurate it is? If your odometer is "under-reporting" miles then your MPG might not be as good as you think it is. I check mine with a GPS, figuring that the GPS is probably more accurate than the odometer, especially considering that I am running larger than stock tires (265/75/16.)
