monte calro gas issue

i recently filled up my 97 monte carlo z34
with a 91 octane fuel
i was preveously using 81 and waited till i was almost on empty to fill up with the 91
after i filled up with th premium gas my car started hesitating and "popping" whenever i accelorate

does any one know why its is doing this and what i can do to help it?

i recently filled up my 97 monte carlo z34
with a 91 octane fuel
i was preveously using 81 and waited till i was almost on empty to fill up with the 91
after i filled up with th premium gas my car started hesitating and "popping" whenever i accelorate

does any one know why its is doing this and what i can do to help it?

where did you get 81 octane????? anyway this sounds like water in the gas.... as you are aware as gas prices go up owners are not buying 91/93 octane this gas is probably old.....and has water in it...