87 740 sunroof does not pause between tilt and open..

There's some microswitches in the gearbox assembly, this will happen if one of those fails. Open it up and you'll see what I mean.

... and don't be too hopeful of finding a replacement for the above mentioned microswitches. My 760 sunroof did the same and you just get good at eyeballing the middle position. Or you can buy the whole part from a yard.

blurp

They look like pretty standard parts, I haven't had to replace them yet but Mouser, All Electronics, Newark, etc ought to have something suitable.

Generally what happens is the dash switch sticks, which keeps a solenoid in the motor assembly energized continuously. This solenoid is not designed to be activated for long periods, overheats and melts. You can remove this and rewind the solenoid if you're real handy with a soldering iron, and in general.