60 + no HHO ?
I had that same car 15 years ago and didn't get more than 40-45 m.p.g. at best ! With what i know now it would be great to have had HHO on that car. As o2 sensors get old and coated in carbon they do not perform as well as new. HHO becomes steam after detonation and cleans as you would expect steam to. I pulled my o2 out after 5000 miles and it was clean of carbon that was there before i started the HHO use! Really cool. If you drove or drive your car a few thousand miles you'll see your gas consumption go up(m.p.g. go down), I'm sure.
Its done right or its not done !
Hail HHO.