More than 400 miles takes work.....
....I have a hard time believing you are getting 400-500 miles out of a full tank of fuel. The only way I see that possible with the 5vz is if you keep rmps below 2,500 for the whole tank of fuel.....
RMP&O: I don't blame you - I've had a hard time wringing that kind of mileage out of the truck! I do keep the rpms below 2,500 - rarely exceeding 65 unless I'm on the short stretch of downhill on I25 between Albuquerque and Isleta. The rest of my commute is pretty flat, but at 5,000 ft rather than sea level. The progression of "best ranges so far" was 405, then 425, then 430, then 450 and finally the 460 (there were other, lower ranges among these). I've checked the odometer against a GPS and it's fine.
There are several tricks - the first is to get an absolutely good fill. I've found that filling the tank fast until the pump shuts off leaves at least a gallon and sometimes 2 gallons out of the tank. I fill slowly from the start.
Another is don't go too slow. Below 45 the mileage drops off just like it does above 60. I'm lucky because most of the commute has a posted limit of 40 - 55 (outside of the interstate) so I can keep pretty close to 50 - 55 on that stretch. I'm usually outside of the commuter rush on the interstate so I can keep it at 65 on the flat, climb at 55 and descend at 65-70 while there.
I don't bother trying to get these ranges in the winter when the ethanol content of our gasoline is high. If possible I like to fill in the early morning when you might get denser gasoline which might provide more energy per gallon (there are different opinions about that).
Approach traffic lights to minimize idling time stopped, accelerate moderately and don't get stuck at train crossings!
The final trick is to get a good feel for how far you can push the "low fuel" warning light. I can't get over 420 miles without driving at least 40 or 50 miles after the light is on.
Edit - I'm also running Michelin All Weather (but not All Terrain) passenger car tires at 40 - 45 lbs (slightly over inflated). I didn't choose these tires - they were on the truck when we inherited it from my father. But I will replace them with something similar as this set has just turned 110,000 miles! That's the best I've ever gotten from a set of tires (they'll need replacement soon).
The 2wd definitely helps the MPG because of less weight and rolling resistance from the front diff.
Is this a manual or automatic? ....I once got an honest 27 mpg out of my Taco, fully loaded with two people. Of course, the circumstances were ideal: I was leaving the mountains and heading mostly downhill, on a freeway, with the cruise control set to about 65.
Martinjmpr - It's an automatic. I had an experience similar to yours with our 2004 double cab tacoma - about 26 mpg when stock (once, but 23 fairly regularly). After new suspension, 255/85/16's, 4.88s, winch, etc. the absolute best I can do is about 21, and 18 is more common. However, I wouldn't change any of that as the Tacoma is the field truck and the 4runner is the daily driver.
Howard L. Snell