What about the gas, is it that crappy ethanol stuff we get here in Georgia? There is a heck of a difference if it's not ethanol supplemented.

Down here, the gas sucks. It's not as good as it was last summer. When last winter came we got the "winter blend" and it doesn't seem like we ever got the "summer blend" back. I'd bet you noticed that in Atlanta as well.
Personally I think they increased our ethanol content all the way to the 10% from whatever it was before.

You may have also just hit the "sweet spot" in your setup, my Jeep seems to respond to premium fuel better than some of the others out there. Especially with the last Flashpaq update.

 

I've had my Flashpaq for two weeks now and here's how it's worked out for me. I've got a 4-Door Sahara automatic with 4.10 gears.

Before Flashpaq
Factory setting with 33" ATZs - Average MPG was upper 15 to lower 16 miles per gallon, RPMs at 70 MPH was 2100.
Factory setting with 35" Goodyear MTR/K - Only went through one tank of gas and it averaged 15.1, couldn't get a good RPM reading at 70 MPH because the transmission was constantly downshifting.

With Flashpaq on 87 setting and 35" MTR/K - went through two tanks, first tank averaged 16.1, second average was 16.07; RPM at 70 MPH is 1900 with no downshifting to maintain speed.

 

That's encouraging Denny!

I'll have MTRs as well!

 

I agree with your logic, but all the pumps around here say "contains 10% ethanol" on them. Sucks, I hate that crap.

 

I add seafoam to anything that requires gas.Ethanol will gum up injectors and about anything it touches....
Seafoam is da shit

 

I never got an update screen, I hooked it up to my home computer for updates.

 

This tank full ran SC on the gas saver mode and got 14.8
Mostly city driving and getting on the throttle abit more the the tank before.

 

I've ran the Mileage XS a couple times on my truck and JK. It always does better in gas mileage than the same Octane level with the performance tune. That said, I have always gotten better mileage with the higher Octane tunes, be they the 91 on the Dodge or the 93 on the Jeep. The other advantage on the Jeep is I rarely have need to downshift at highway speeds with the 93 Octane.

As for cost/efficiency, paying the extra 20¢ per gallon on premium doesn't make economical sense until gas prices are above $3 per gallon. That's when the extra mileage starts paying for itself with the extra 20¢. It's kind of funny as when the gas prices climb it's a bit counterintuitive to opt for paying even more for fuel.

 

I guess it's time to move from 87 to 91 then. Prices are over 3 bucks in So Cal.

 

I would do your own tests first to see how much your mileage increases before adopting what works for me. There isn't any hard and fast rules here, but I would definitely run a tank full of premium and make the comparison, then figure out your cost per mile.