Ford's answers to the NHTSA 6.7 Investigation

I am a "by the book" type of guy... I read the Owners Manual, figure the folks that design these things know what is best for them and what to run them on, and really don't feel the need to experiment with fuels that have iodine numbers associated with them. Dinosaur numbers work for me, and anything close to 50 cetane like we get works plenty good enough for me. I can say with certainty that some additives, like for example Power Service silver bottle, will absolutely increase my MPG if I am doing highway speeds for extended rates of time, compared to untreated fuel. I can also say that stinky, highly aromatic fuel as was found in Utah, Montana, and especially Wyoming is especially good as steady state Interstate cruise fuel, but far more smokey out the tail pipe when used as stop and go city fuel. This was prior to 2007 ULSD being mandated. Many states have lowered the percentage allowed, aromatic wise, in their fuel. I am sure it has lowered the energy per gallon of the fuel we buy these days, there's less K cals per gallon now than before.

Just some observations I've noticed over the years as a diesel head.