Reasonable assumption. I heard somewhere though that the ethanol content was instead deduced by the O2 sensor in the exhaust. I don't think the 21-23's have a dedicated O2 sensor. I'm wondering if they just didn't want to do another epa mileage test who knows...If they no longer support flex fuel, they may have deleted the ethanol sensor to save money. Likely a result of people not using it enough to warrant putting it in the vehicle, aka cost savings. If such is the case, no you cannot run e85 because it can't be detected and accounted for by the PCM.
Ford wasn't using an ethanol sensor like GM did. They had a virtual sensor. So it certainly seemed like a mostly software solution.If they no longer support flex fuel, they may have deleted the ethanol sensor to save money. Likely a result of people not using it enough to warrant putting it in the vehicle, aka cost savings. If such is the case, no you cannot run e85 because it can't be detected and accounted for by the PCM.
My '21 doesn't have a gas cap and I don't think any of them do.As of today 6/1/24 the Ford website still lists the recommended fuel for the F150 5.0 V8 as regular unleaded or E85. All other engines only say regular unleaded.
I had planned to run E85 in my truck which is currently being shipped. If it arrives with the yellow gas cap, I will run E85.