Good info here gents. Thanks.

 

I know this is an old thread but I have an issue with my 2019 F150 5.0. The first year I owned it I ran 93 only fuel in it. Obviously now it's getting expensive so I started running 87. It seems like every time I fill the tank, and I have tried multiple stations and brands, the truck starts prefiring like crazy. I originally thought I got bad gas but 4 different stations and all had the same result. Dry gas, fuel system cleaner also made no difference. I finally got forscan and looked at the ethanol content reading and it was showing anywhere from 60 to 80% ethanol. Stations here run around 10%. I cleared the adaptations and reset the computer and watched the live data and it drops to about 10% almost immediately and it runs fine until I fill it again. Like most people I figured I had a sensor for ethanol content but according to this post it's done by calculation not a sensor. So, the question is what the heck is going on with my truck? anyone have any ideas? If I run 93 I have no issues. I only have 33K on the clock.

 

I feel like there was a thread in the last month or so with the same issue. Ill try to find it

 

Afer filling, the truck goes through ethanol/octane calculation and with 87 will have quite a bit of retarding to do. Try a full KAM reset if you can and go from there

 

I've done that 3 times.