knockin and pingin!!!!

well, last night I filled up with Shell 91 octane gas instead of the usual Chevron 94 ( shell was 7 cents cheaper ) - big mistake. My car is now knocking like crazy under boost

if I tossed a bottle of 104 octane boost would that help???
or maybe just drive like a sane person till I need gas again ( yeah, right lol )

has anyone ever had this kind of problem with 91 octane stuff before??? I used to use it but not with this result....

Ohhh yeah,just don't go to much on the boost side Brad.Add an octane booster.Later.

Ohhh that sucks Brad, keep the 94 in there, cause if you figure out the 7 cent difference to 60 litre tank thats only a difference or $4.20, i'm sure the bottle of octane boost cost more then that. Anyway good luck and stay with the 94!! your car is just telling you what it wants

hmm pinging with 91...my car only ever gets 91 or 92...don't think i've ever even seen 94 or anything like that!

Generally speaking, Brad, the 91 shouldn't be the
cause of that: Something else probably is...since
u had it in storage all winter, under what (?)
storage "prep'ed" status??? While 94 "assisted" the
present condition of your engine, the 91 allowed
some "weakness" to manifest itself....lol!

Anyway, try running a couple small bottles of the
injection cleaner stuff in the gas tank, due to its
size I recommend two bots... In case you've got
accummulated moisture (etc.) in their, that will
help. Come to think of it, the red STP 'gas trtmt.'
is specifically for absorbing uer moisture and can
be added in addition to the injec clnr stuff....
Also, with the engine cold and running, spray some carb cleaner thru the throttle while lightly gunning the rpm with uer left hand...

Aside from that, other issues might be at play,
like when was a tuneup last done??? Etc.

In my MN12's: 91 runs perfectly fine. Just that 94
runs even more perfectly...lol! BUT neither causes
the symptoms u describe.

A last reflection could be u accidently accessed
some old gas, or stuff at the bottom of their tank
which u can't be expected to quantify!
Ideally, when in town, as Jamie states, always use
the 94 mainly due to its "best" status. It is also
specifically recommended by Harley Davidson, for
what it's worth! BUT, it "tends" not to be available
outside major cities, and one necessarily turns to
91 anyway...lol! Peace, virgil