The only O2 sensor I can find for a 97 HX is over $400. It is the five wire before the cat convertor. Does anybody know where to find one cheaper? It is ridiculous that the one after the cat is less than $100, but it is 4 wire. I don't get the difference.

 

I have bought all mine from densoproducts.com. Its basically sparkplugs.com, just with different graphics, they are essentially the same site. They sell Denso sensors, which is the OEM for Hondas 1996 and on (I can't remember if they are prior to 96). They are the best you can buy, and the ones that were in your car from the factory. Try this site out, I bought the primary sensor for my 98 LX for like $60, and the secondary was a little more, like $85. But either way, a lot better than the dealer price. Their shipping is pretty low and they come in a sealed package in a denso box, so they are legit, if you were worried. The 5 wire sounded strange to me, but I forgot the HX has a D16Y5 and that does have a different primary sensor than the rest. I'm not sure what it'll be like on this site...good luck.