I've noticed one of the biggest factors for me when it comes to fuel milage comes down to the oil. If I run 10w-40 I seem to get about 2-3 mpg less on average, where as with 10w-30 I seem to do a little better. Of course there are other things to take in to account, such as time of year. In montana they have been adding 10% ethanol (missoula/bitterroot valley) in the winter months and back in idaho they haven't been adding anything. Now I'm running full synthetic 10W-30 and it seems to make my mileage higher and more consistent. Just a thought

86 4runner, pro comp AAL, Kayline Soft top, 31's but all stock