Mine had a knock. I drove it for about a year and my dad drove it for about 1. Its really bad now so its parked and i switched to the Fiero until we get a new motor in it or rebuild it. Just had to shift early and no high rpms.
Could just be the wrist pin is a little worn. Suprisingly quite a few jeeps have this. Mines been knocking since the day I bought it. Still runs strong even after I put 20,000 miles on it. Don't sweat it I wouldnt be suprised if you got another 100k out of it. It seems that thats how mines heading.