im a new member and new hybrid owner. I have had a 2008 base model w/ 3rd row seat Highlander Hybrid for 3 1/2 weeks now. The 1st week I averaged 27mpg in city and 26mpg highway. The next week I got 25/city and 23/highway. Now I am only getting 21-22mpg in the city. I've tried that mid level gas (tween reg and prem) w/o results. The mechanic at the dealership didn't have a clue. Anybody else doing this poorly. Any way to improve. Oh and our temps are 80+ degrees.