Oxygenated fuel might just do the trick.  However - you might already
be using it.

Could be you need a new O2 sensor as a long-term solution.

    Do you have a new air filter?  HC is gasoline vapor so maybe a new
air filter will lean out mixture and help it burn better. Try changing
your oil it accumulates gasoline after awhile and the gasoline vapors
get sucked into engine through PCV valve.  Changing the oil is the
first thing I would try.  Also make sure gasoline vapor canister has a
clean filter, also could try a new set of plugs, and clean out pcv
valve.

If the car was not thoroughly warmed up before the test, try it again after driving about 10 miles at highway speeds. New sparkplugs would probably make enough difference to pass.