My 92 Explorer has chronically been fussy about starting. We have blamed
various brands of gasoline as well as things like winter/summer blends and
off brand stations.

The symptom has been that a cold engine took two tries before it would fire
up. experiments like waiting with the key in the run position, changing air
filter, cleaning IAC, etc. have shown no difference. Problem might go away
for a while but always returned.

Recently I filled up with an off-brand that was a few cents cheaper and the
SUV started nicely every time.  At the second fill up at the same station, I
noticed a sticker on the pump that advised that he fuel contained 10 %
ethanol.

My limited search on the internet found that the ethanol raised the octane
rating of the gas. There was nothing I could find regarding starting
effects. I understand that the higher the octane, the harder it is to ignite
the fuel air mixture. This is why higher octane gas inhibits engine knock.
This makes it counter intuitive that the ethanol would enhance starting. It
ought to make it harder to start. The 92 service manual when addressing hard
starting complaints advises that the use of higher octane fuels may be the
cause and that the user is advised to stick with 87 octane.

So what I have is a contradiction. ethanol, raising the octane should make
starting more difficult. In practice it almost seems as if the ethanol acts
like a starting fluid.

What is the experience of other users, especially those with the older 6
cylinder engines?

Charlie