I am going to go look at a 92 mark VII tomorrow it looks nice in pictures but what should I be aware of? What usually goes wrong?

Big things are the air ride and ABS. Air ride you should be used to if you have a Mark VIII. The front bags on the VIIs are not part of the strut so they are cheaper and easier to change. The ABS can be expensive to fix depending what's wrong. I'm sure there are some other things I can't remember now but the drivtrain is pretty solid, 5.0L HO/AOD/8.8 rear.