100% certain the noise was pinging
I run 93 octane always.
Thats what it says in the manual anyways.
It shouldn't be necessary.
My manual says use 86 or higher.
Keep in mind that the manual states that the numbering system the 86 is PON based, not MON nor RON.
IF by chance your local pumps are RON based, then 86 is too low.
(RON# + MON# / 2 = PON#)
RON is Research Octane Number.
MON is Motor Octane Number.
PON is Pump Octane Number.
For any given gasoline, it's MON # is lowest, it's RON # is highest, and it's PON # is right in the middle.
While I'm at it, re gasoline that is, the manual also says:
10% Ethanol limit. ( by volume)
5 % Methanol limit but must have cosolvent(s) and inhibitor(s).
15 % MTBE
Unstated but understood is 10 % Eth or 5 % Meth or 15 % MTBE, no combinations.
Stating"93" alone in this day and age is borderline meaningless in terms of categorizing a gasoline.