I have a flex fuel gmc sierra with the 5.3 V-8. I was wondering what kind of mileage increase I could see, by taking it to a local guy that has hp tuners. Maybe 1 to 2 mpg? The problem I see here, if that I want to use E85, will that mess up the truck, since the truck will be tuned for regular gasoline? Or maybe he can just tune the low octane table and leave the high octane table alone, since the high octane table is for ethanol anyway. What is everybody's thoughts?

 

I tuned a friends 07 classic flex fuel.
He gained a couple mpg.
You don't need to do anything special when tuning a flex fuel truck.
Tune the timing for gas and you will have no problems on E85.
The high octane table is not just an E85 table.

He is very happy with his 87 octane tune.
It makes a very noticeable difference.

Do it.

 

hello
i wanted to tell that we can take care of that for you. they way your truck is running now, it would like that but even better with E85 or gasoline. the computer adjusts itself, and we can take care a/f ratio tables, ect
thanks
hope i can help
melissa

 

Thanks for the offer, but I have a local guy that tune while I drive. Its safer to have it tuned in person. On my 01 pickup, it had a wester's tune, and it was picking up knock, even under light acceleration. So, he fixed that and I can say it runs a lot smoother now.