My 08 Sant Fe, with the 2.7 lawnmower engine normally does fine around these parts and gets about 21 mpg highway BUT we've recently had a bout of hot humid weather with temps in the 90s and high dew points. Performance SUCKS in this weather. I have to bump it into passing gear to get moving....and gas mileage has dropped to around 13 mpg. My regular gas company has had problems in the past with crappy gasoline so I decided to try Shell. MUCH better. I also had to add some Gumout to the tank to clean things up. Anybody else got these problems in hot weather? If I had a shell station locally, Id run that fulltime but I have to go about 40 miles to find one. ALL of our gas here in this county is supplied by United Refinery, a local outfit. Sure would be nice to have a little competition!