My 97 855 was acting strange -- okay around town, but on the highway it lacked power, shifted at unusual times, and was running hotter than usual (not hot just a bit hotter than normal). No indicator lights at all. I first thought it might be some sort of blockage in the air filter, but nope. Suspected some weird PNP problem. Nope. Finally Royalty Auto in Somersworth NH (a great independent shop, if you're in the area) diagnosed it -- in about a minute flat. Clogged catalytic converter. Couldn't be easier to fix. Expensive part, but at least the labor is minimal.

I was close in my initial diagnosis, just on the wrong side of the engine. Problem with the cat never crossed my mind. Anyway, something to consider if you see symptoms like I had.