Have a little insight into this. Picked up a '00 cheap a couple years ago myself. Running but not really driveable. Spent the last 2 years fixing her up. There is a good chance this is a CA Emissions vehicle. Mine is. Not sorry I bought it but stuff would be easier and cheaper if it weren't. They did make federal emissions ones but if you do not live in CA and it is I would think about long and hard about buying it. Biggest thing. The head. Casting # 0331. Poor casting from the factory causing some of them to crack. Kinda under the impression that a more severe overheating of the engine might help this come about. Symptoms seem to include unexplained loss of anti-freeze, milky looking oil, and little or no oil pressure at a very hot idle. The loss of anti-freeze you can not really tell. You can take it for a good ride, get her nice and hot, and see what the pressure is at an idle. After you do that turn her off, leave the hood closed, go to restart her in about 20 minutes. This is to see if she has heat soak issues. The heat in the engine compartment vaporizes the fuel in the injectors and/or fuel rail. Making it rough starting for a couple seconds. Check the oil, look at the oil filler cap and check in the valve cover for the milky looking oil which would indicate a coolant leak. Things I have come across with mine. Windows only working from the driver's door. Window lock switch is messed up and won't let passengers roll down their own windows. Just replaced the control. Passenger speaker not working. Just a broken wire in the door. Drivers side window would not stop trying to go up with finger on the switch. Little worm gear stripped in regulator. Just replaced it. Usual valve cover gasket leak. Plus I think the leaking oil dripping down on my starter made it start acting up. Try to check for death wobble. You hit a bump at about 50mph and the Jeep starts shaking bad. Simple fix is the steering damper but sometimes just masks a more serious problem. Tough to make it happen on command too. Rear hatch not wanting to open. Most times just an adjustment. Look underneath. Some rust pretty good. Just so you know the Jeep does not have a frame. Is a Uni-Body. They still rot to. Jeeps leak. Most times on the passenger side. Sometimes from the windshield, cowl, or from a plugged up A/C discharge tube. So check the floor really good especially on that side. Probably a couple other things I could mention. Most of this is more common so googling it should give you more insight. Sorry for the verbal vomit but I just typed things as they came to me.
