Hard to say.

Could be the fuel pump is sucking filth as the tank runs near empty.

Could be the higher octane is assisting a weak spark, due to a weak coil.

Can you give a maintenance history on this car? And answer the other
questions asked?

Otherwise, don't expect a response...

"Pd7704" <brian.polson@greatwesternbank.com> wrote
>I just posted a topic called my (90 accord idles rough when stopping), I
> drove the fuel down low and filled 3/4 up of Amoco ultimate or 92 octane
> for those who don't know what Amoco ultimate is, now the problems seem to
> be gone is there a gas tank or fuel pump problem when the tank gets low
> has anyone heard of this before? read both articles to better understand
> please!!!! Any ideas????????
>