Just an update, because I said that I would give you one...So I filled up with Shell on my last 2 fill ups now...I only have 70ish miles on the second tank, but on my first tank of Shell, I noticed a 1 MPG increase over the previous tank and .6 MPG increase over the tank before that (both ARCO, cheap gas). I am giving you these two tanks, because I can verify the driving on these (which is listed in a second) and know for sure where I filled up...

Most of my driving is 15mi each way to and from school (about 3-4 miles of that is city and the rest is 55 mph highway) and a little bit of around town driving where my truck barely gets to operating temp before it gets shut off...the weather has been crappy on the last tank (shell) and I drove it pretty hard just because...I don't know where I fill up every time, but I am starting to keep track now...

Oh yeah...The milage was 12.9 which is actually a little bitt higher than average.