I also recently purchased a 1995 850, but with 311,000 km on the odometer! I had the intermittent problem with the shifter. However, whenever it happened, the ABS light would stay on. I just jiggled the ignition or swithched the engine on and off, and the problem went away. I was having other stuff done at the dealership, so I asked them to look at it. They said it was probably a solenoid. They said that if I didn't get it fixed, it would get worse, but that I wouldn't be up a creek without a paddle. I decided to have it fixed anyways. It cost me Cdn $93.03 for the solenoid, 19.92 to replace two light bulbs in the shifter and 1/2 hour labour. (multiply my dollar amounts by 2/3 for a good approximation of US dollar amounts).

Now I'll wait and see if that takes care of it. They checked my ABS and didn't find any codes and that they worked fine in a road test.