I think you might just be freaking yourself out while searching the forums for the problems you're having, thinking everyone is driving money pits that break all the time. It sounds like you bought a neglected vehicle unfortunately, and you may have to work through some quirks before you get the reliable vehicle you thought you were buying. I bought my WJ not realizing the number of issues it had because of poor maintenance from the last guy. I felt like I was fixing things constantly and it was a pit, but after a couple months, I completed the last repair, and it was totally trouble free for the next 2 years I had it. I've had my XK for 6 months with nothing more than a loose vacuum hose and a squeaky navigation disc.
My advice is to work through the issues you see and once you crest the hill, you'll have the vehicle you thought you bought originally. I'm sorry to hear about your luck, but these aren't crappy, unreliable platforms.