Diablosport Forums

I am looking to tune my GMC sierra to get better fuel economy. I just purchased the Diablo Sport Intune I3. I run 87 octane, and tires are LT265/70R18 which is only one size up from stock. I bought the truck used so I am not sure if it has been tuned in the past. I just bought a K&N cold air intake which I have not installed on truck yet. I am only getting 10 to 10.3 miles a gallon max. I have run 89 octane and fuel mileage stays the same. Truck lags when you hit the gas. No power at all. Please help me tune this truck. Any suggestions would be great. Thanks!

Id suggest trying the 93 tune if you are looking for more power, it will make the best gains when used with 93 fuel.

HI Mike. Where do I find the 93 tune. Thanks!

Tune Vehicle - Advanced Mode...

select the ECM tune called "Diablo Tune" - that's the 91/93 octane tune...

and then choose the Firm Shift tune for the transmission/TCM tune...