[Slopfrog]

I have a 2005 Kia Spectra 5 (auto unfortunately) which I recently bought for a commuter car, since driving my truck was killing me financially , plus I felt guilty about the pollution and lining the pockets of big oil, countries hostile to America, trade deficits, etc. etc.

Well, the car's first tank got me a whopping 25 mpg, even though virtually all my commute is highway. Which means I was losing money on the deal by the time I paid for insurance on the thing. This led me to try hypermiling.

My first tank after doing so was 30.6 mpg. For a small 4 cylinder car I am unsatisfied... Driving without AC (which in Florida is hot even in December), no defroster, granny starts and stops, coasting in neutral for painfully long distances, 60 mph on the interstate, etc... I don't want to sound entitled to better fuel economy but I was expecting the payoff to be a bit better.

I have a sneaking suspicion my tires are working against me. I have them at 40 psig rear and the max of 44 psig in the front, yet they STILL look like they're low on air in the front. Of course, they're brand new so I'm stuck with them. They're Firestone Affinity and they seem to have sidewalls built of mud. Has anybody else experienced similar issues with tires?

Any other ideas? I need an aftermarket cruise control anyway to save my foot, and since the only hills around are interstate overpasses and bridges I think it will help me a little by maintains better throttle control than my tired ankle can manage to do. Thanks!