GEN 1 To catch a tuner...

[MFNG]

Just found 93 octane (E-10) around me and decided to try a tank. Was using 91 ethanol free before. My MPG jumped from 11 to 13 instantly. Haven’t seen above 11.5 for the 5k I’ve had it. Drove around town for 10 miles stop-n-go and it’s holding at 13+/-.

Does this sound like there’s a 93 tune on it that I wasn’t aware of (bought used)? How can I tell if there has been a tune out on without going to a dealer or buying a forscan device?

 

[B E N]

It sounds like your getting some knock, and the extra octane is helping with it. It could be a tune, but it could also be and is more likely a mechanical issue. Clean your MAF, check the condition of your ignition system, check for stored DTC. You may have some carbon build up in the cylinders, do you ever run it hard? Your mileage is pretty low, I get above 14 untuned and 15-16 with a tune loaded on 87 (I don't hammer it at every opportunity though).

The trucks were designed to run well on low grade fuel, you shouldn't need premium. E10 is also fine in these trucks, 10% ethanol means less toluene, benzene and xylene so unless your storing the vehicle for long periods with fuel in the tank your better off to run the blended fuel.

As far as figuring out if there is a tune on it, you need to take it to someone who can look at the file that is on the ECM, meaning a tuner or dealer. If you have a friend that uses HPtuners they can do a file comparison and tell you in just a few minutes. The best thing you can do if your concerned about it is take it to your dealer and ask them to flash on the most recent calibration, it will cost you $100-200.