Robertpitre

WOW, i've never even seen 9.5 nevermind 8.5. i've been down to 9.8 maybe, at best on higway in Rockland.

On another note. I asked my dealer to Flash it 2 weeks ago and he said no.

twistedkranch

It seems to help if you use premium fuel as well. I have an 07 Rubicon, basically stock. I made a little excel chart and ran all the numbers after monitoring mileage #'s on both regular and premium fuel. I saved about $4.50 filling with regular, but found that I got the equivalent of $6.00 more mileage out of the premium. Please note, it will take at least to the second tank of premium to get the other stuff cleared. It also helps if you use the cruise....

JTPhoto JK

My findings as well with my 08. I found a good balance is to run Premium every 3rd tank full. Keeps the computer on its toes and really seems to give the best seat of the pants feel.
My daughters 09 doesn't seem to see the same benefit with the premium.