Robert wrote, 

>>At high elevation there is less oxygen so a fuel
>>injected engine will compensate with less fuel 
>>better mileage perhaps but less power. 

At higher elevations there is also less air to push. The best our '85 Westfalia has ever run was two falls ago when we were driving across Montana on I90 and I94 from around the continental divide toward Billings and Glendive. The weather was cool and there was not much wind. I was driving at about 110 kph (4000 rpm) but the van kept creeping up toward 120 kph (4400 rpm) I did not check the gas mileage for this particular section but it was no worse than normal. My point is that the van wanted to go faster than normal and seemed to have more power than normal. (It seemed like we had a nice tail wind but we did not.) The only difference I could see was the higher elevation. Higher elevation equals less air density, equals less air resistance for the van to push. As Robert noted the FI system keeps the oxygen to fuel ratio constant at higher elevations.  

Has anyone else noticed their van running better at higher elevations? 

George, 

'85 Westfalia