Where is the O2 sensor on a 2000 jeep wrangler?

Well, honey, the O2 sensor on a 2000 Jeep Wrangler is located in the exhaust system. Specifically, you'll find it either before or after the catalytic converter. Just get under that Jeep and follow the exhaust pipe until you spot a little sensor sticking out - that's your O2 sensor. Now, go get your hands dirty and fix that sucker!