eesh, that hc is really high. Is that plug gap correct? My 87 civic plug gap should be 1 mm to 1.1 mm, which is .39 in to .43 in.

Do you have a carb or a fuel injected car? It could be your carb is giving you a rich mix or your fuel injectors are getting stuck open for longer than they should be. If it's either of these two...seafoam can clean out your carb/injectors partially, though nothing matches a rebuild or new part. If you don't mind a retest in the event of another fail, I'd try putting seafoam in your gas and into your carb or a vacuum line.