All this is likely why I found it with B7ES spark plugs in it.My rule of thumb.... if you're not sure, treat it as detonation.
Kinda like when I lived in places with King and Coral snakes....
Instructor: the color bands are ordered different... it's easy to tell the difference.
Me: don't give a fuck, they're ALL coral snakes far as I'm concerned.
Instructor: learn the difference or fail my course.
Me: least I ain't gonna screw it up and die if I go with my plan.
*actual conversation I had...