not unless you have a high performance motor. This is about the only way you would notice a difference. The reason is air is thinner, higher up, and six thousand feet the air is a lot thinner than sea level. also, cold air is denser (and therefore your car will run better) than hot air. In modern stock fuel injected cars, the computer adjusts the mix and the effect is less noticeable in part because air/fuel mix is injected into the cylinder. On carburetors automobiles, there is a noticeable power loss, because the car has less air, and more fuel because the air pressure is less. you may notice when you get to sea level, that when you step on the gas first thing in the morning, your car will rocket off faster than you meant too, but of course after that you will compensate, on a long drive, I like to run chevron super unleaded in my car, this company has techron a fuel system cleaner already in the fuel, and super will let the combustion chamber get good and hot, which helps burn off any impurities that may build up over time from puttering around a nice long drive on the freeway, particularly in a v8 can do wonders.
