So a few months ago I moved from Colorado (~6400ft above sea level) to Florida (~10ft above sea level). Immediately after I moved the fuel efficiency in my car dropped significantly. Previously I was getting 27-28mpg, and now I'm getting 22-23mpg.
I would have expected the opposite as now the engine gets more oxygen so I would think it runs better. And indeed I've seen several sites on the internet supporting this. Unfortunately I've also seen several sites claiming the opposite.
Which is it supposed to be? And why?
If I am supposed to be getting better fuel economy at lower altitude, any ideas what could be wrong?
I'm measuring fuel economy by how much fuel the car takes at the pump & my odometer. I've tried resetting my ECU, which had no effect. My driving has changed a little, but is more freeway driving now.
Car is a 2002 Mitsubishi Eclipse Spyder. Its a 6-cylinder manual transmission. Uses premium fuel (89 in Colorado, 93 in Florida).