Good morning

I have a 2022 F150 5.0 STX that is flex fuel capable. I have a 91/93 tune so I cannot run E85 anymore. I recently took it to my dealer for service and they made me put the truck back to stock. Since it is now back to stock am I able to run e85 now??

 

My WAG is yes but why not shoot a question off to your tuner? I'd also be curious why you couldn't run E85 as it's about 100 octane. I'm well aware of density and BTU content.

 

E85 needs a 30% richer air/fuel mix. When tuned for 93 the a/f and spark timing are much different than E85. Probably out of the ECU adjustment range. KM

 

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Yes you can run E85 if back to stock program.
Truth is these engines in stock form can't use much past E40 but you have little choice from most pumps. This has been proven in Dyno testing to see.
Octane is not the whole story.
My 2018 can run E85 anytime but normally don't go beyond E10 or E15.
Good luck.

 

If your back to stock, yes you should be able too.

 

OZ tuning lets you run any octane on their tune. Since you are back to stock you can run E85.