What I wonder, too is what if your car is under warranty?  If the manual
says 87 octane, and you put Colorado's 85 octane gas in, you might have
just voided the warranty, high altitude or not.

Personally, I try to run what the manual for the vehicle says, regardless
of what the regional fuel monopoly is trying to push as "regular".  I
figure whoever wrote the manual knew what they were talking about.

             _ _
  __ _ _   _| | |  | David M. Brodbeck (N8SRE)              Ypsilanti, MI
 / _` | | | | | |  +-----------------------------------------------------
| (_| | |_| | | | @ cyberspace.org
 \__, |\__,_|_|_| "The United States does not have a security system.  It
 |___/             has a system for bothering people." -- Sholomo Dror,
                   when asked about U.S. airport security.