[Formulajones]

I've never run out of gas living at the higher altitude and to be honest there isn't a huge mpg difference I've calculated from driving up here or at sea level.

Basically if it helps others to put a number on it, from what I've seen on the AFR gauge at 6000 feet vs sea level is about 1 point in AFR.

So I generally tune the carbed cars to be a pinch rich up here and they daily drive just fine like that, then when I drive down to sea level they are still in a happy spot. What you absolutely don't want to do is lean it out up here and then drive down to sea level where it'll lean out more on it's own and put the engine in a dangerous spot.

For instance the daily drivers cruise around upper 12's to low 13's AFR when we are a mile up. That leans out to upper 13's at sea level. Basically I just live with them being a little fat at elevation and that works just fine, doesn't really affect gas mileage and the plugs stay clean.

Ideally EFI that has close loop compensation has an advantage in this scenario as it will keep the AFR you want no matter what atmosphere your in. We did switch 2 other cars over to EFI for that reason, and I'll admit it's pretty sweet.