I don't run better fuel to see if it makes a difference, I run it because it does.
My 1986 D-250 I bought in 2003, since that day I always ran Amoco premium in it.
In this case the octane did make a mpg difference, it was an NA carbed intake.
In 2006 I had a fuel related problem and the mechanics had to tear apart the carb.
I was standing over the side when one of them said 'wow this carb is clean,' so I looked...
And it was, once inside the carb the metal parts were like brand new, super shiny, not a speck of gunk or dirt, I've never seen one that clean unless it was fresh out the box.
Wasn't the carb
Guess I could've told them that, but I don't back talk my mechanic.
I did tell them this:
Yes sir, I always run Amoco premium.
Once I switched I never looked back.
Even my lawn mower and my weed eater runs BP 93.
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