I think you made a smart move by taking out a little air from your tires. I feel their comes a point of no return, and too much tire pressure is a leading cause of wear to the sides of tires while the center tread may seem much newer. It happen to me in a previous pickup.
BTW: My tire pressure was going down along with the average temperature outside, and it kept sliding downward until I started seeing 35/36 PPSI I figured it was time to raise it back up close to the MAX again. I filled up all 4 tires to 40 ppsi COLD, and on warmer days and/or long trips my pressure gets up to 43ppsi. That's exactly where I like it- 1 found on a warmer day with a lot on miles put on it, as long as it does not go above 44, as Goodyear has put that number on the tire for a reason, then I am most happy. Too much tire pressure makes taking corners difficult too. The first thing I noticed with the higher gas mileage! I gained 3/10ths on my AVG MPG Display- right from the get-go!! Now my record high is 45.7 MPG AVG - I have a picture in my album folder on profile here, and it is also in the thread out my car in Success Stories.
I really do believe my car is very near it's max with fuel economy unless something like an oil change and tire rotation might help, because that is the next big thing for me to do, and for as little $$ they charge I might have it done in town and stand back and watch them so they can get spooked1 haha- Naw, I can normally trust these kids to do what they say. For the price of the oil and lube, not to mention my own lack of knowledge, I don't think it's too bad a deal for what this little place in town charges. I just hope getting all of that break-in oil out might help my MPG, at least a few tenths
Here is MY All Time Mileage Record for my 2009 Cobalt XFE starting on the very day I picked it up brand new with 133 miles on the odometer and 25 MPG AVG (the dealer had the car driven over from out of state which I had agreed too) - The MPG gauge has NOT be reset, but I am aware of how to do it if I choose to. I just rather have an all time average for the time being. I am having a hard time getting above this record of 45.7, but I can see that my odometer is on a path way of ever so slowly making it higher, and that includes short trips in 70MPH zones.
WOW 45-55 MPG driving CHEVYs! Whoa would of "thunked it" a couple years ago?? Just today I was directly behind a Toyota Prius Hybrid and I got to thinking to myself... I bet this driver don't practice hypermiling. And if he does not, I would think it's mileage is close to the EPA reported 50MPG. In which case the OP here has already shown an inexpensive Chevy can do it, and I'm darn close behind. Then I think about the difference in the price of the cars, and I know I made the right choice. I admit I am impressed by the hybrid Prius. But for the price my Cobalt cost me, and the fact I am almost getting 46 AVG MPG all time driving, well it just makes me smile. What is not so cool is that I still have yet to see another Cobalt XFE in this county!! I think I am the only one, and it certainly would explain why the police often glance my direction just long enough to see me and then go another way. They leave me with an impression they know my car, and with that 7 foot cb antenna and the rest, it makes sense.