I just got the new flash last week. On my last tank of gas, I got 22.26 mpg. This was 95%highway driving. Prior to that, I averaged around 20.5 mpg (on the highway). I really haven't noticed any other differences.

 

ya gotta be shittin me....22 mpg....no friggin way. go back and check it again

 

I average 21-22 with the R flash and live in Wyoming. 80% highway driving 70 MPH

 

keep in mind your fuel trims get reset during the flashing process... leave them stabilize after a few weeks then check back

 

The car is relatively new and after reading all of the posts about the crappy mileage, I am as surprised as you are. I got 307.5 miles out of the tank and when I filled it up, it took 13.812 gallons. Looks like 22.26 mpg. The Mustang GT Vert I just sold got between 23 - 24 mpg on the same stretch of highway. It's engine was almost 4 times as big, so the mileage doesn't look that great to me. It didn't need premium either.

 

according to the manual, the rx8 doesn't need premium either :p

 

I just got 252 miles on 10.003 gallons (and it spilled out of the nozzle)

 

I still have the M flash. should I get the latest? car seems to run ok but mileage sucks,would the update help?

 

You'll have to get R when you take your car in for the recall, so just wait it out.

 

My last fill and I'm not sure what flash I'm on was 13.23 gal and I was at 266 miles. 20.01 MPG and I drive the **** out of my car.

 

damn you guys, i only get about 170 miles out of a tank of gas...though that's with all stop-and-go driving and high revs every shift.

 

I just got the R flash and I had the M before. Bottom line: "DON'T GET IT!!!"

Mileage SUCKS now!! I used to get 20-21 MPG... now even with 90% HWY I am barely getting 18.5MPG!!!

I tend to be below 3750 RPM on 6th gear so the secondary port doesn't kick in and still mileage SUCKS.

On top of this $3.19/gallon is not helping! Guess I'll start using 87 octane from now on... My wallet is definitely suffering... "Thank you Mr. Bush!!"

Carlos

 

Interesting. I'm on the M flash and getting barely 20 mpg with all highway driving. Anything involving stop and go driving drops me to 18 or lower. Seems like there isn't a lot of consistancy between what happens when you get your ECU flashed.

 

im on N i cant break 16 mpg if my life. I did break it comming from disney at 74 miles per hour with cruise on , i only got 18 mpg when i had k or l i was getting 19s city and highway and 22 with cruise controll

 

Looks like it depends on the driver and how lucky you are to find a flash your car likes the best