We are currrently on the east coast in New England so I have no issues with our 2000 with the 3.4 for daily use. I get a consistant 17.5 mpg avg. and no problem with power in our 4x4 5sp. However, we'll be moving to NM in the next few years and at 6,000' + I'm wondering if the stock 3.4 w/automatic 4x4 is enuf to haul us around at higher elevations. We don't plan on towing anything just the a camping load in the Runner for up in the hills. I have 4.7 in the Tundra but the mileage bloze, usually in the 12's so I'm happy with a 3.4 if it will do the job. Any opines?