Pete,
Thanks for the reply. However, I did have a situation (very strange one,) that a Ford TSB mentioned using winter grade fuels during warm weather. The specifics were with a little less than 1/4 of a tank and hard acceleration, the engine would buck above 4K RPM. I filled the tank up and it went away.
I do remember that MTBE was used or an oxygenate, but now banned. However, I think that ETBE is still being used. The oxygenates are for the so called "clean fuels", but the refiners use other mixtures to control evaporation point (temperature based,). My condition above was due to vapor lock in the fuel line from the particular situation
1. Low fuel level
2. Warm weather
3. Winter grade fuels.
Of course, since gasoline is made up of about 150 types of chemicals/hydrocarbon chain combinations, it's difficult to know what changes they do for each geographic region and each temperature season.
David
