OT: BMW help, Please :) Options

[Loser_Cruiser]

I figure from the many members we have on here I should be able to get some usable feedback on here.

About 6 months ago my sisters 95 (OBD1) 318i Convertible automatic transmission developed a horrible oil leak. Since I was away at school and my dad was traveling they took it to a shop to be repaired. Shortly there after the car started dieing on her. The oil leak was caused by a bad oil filter console seal or something along those lines.

The car runs and idles smoothly, the car dieing is intermittant and hard to reproduce (unless your trying to get somewhere).
Since then it has been in and out of different shops for the last 5 months. The reason I want to fix it is because she is going to buy a new car and I can have it.

The different shops have tried the following; adjusting the immobilizer chip in the ignition, dash cluster replaced, checking the fuel pump, crankshaft position sensor and fuel filter.

The car drives perfect till it dies. Following it dieing it won't always start back up for along time. The car may run for hours and then die or minutes.

What should I try to check? The car is at my parents house(5 hrs away) when I go to visit I am going to check it out a bit and maybe bring it back with me to work on.

Thanks everyone.