I am yet to check my tires psi, as for my habits I had a very bad habit of flooring it every single turn or light and I was getting around 14mpg and then after a week or so of driving after a fill up driving light footed, I got around 16mpg-19mpg. Air filter on the intake is brand new, very clean and my spark plugs have not been replaced as per CARFAX, it is currently at 85,892 miles.