I swear that my VX is the only vehicle I have owned that gets better mpg with hotter weather. I got my best mileage on I15 out in the Mohave desert @ 95 degrees and relatively flat highway allowed me to get 23 mpg with Bridgestone Revo A/T's iirc 265-75-r16. Yes, repl fuel pressure regulator if it needs repl gives you a couple mpg too.