1994 Mercedes Benz 500sl Stalls after 15 minutes of driving

I had the same problem, I have a 560 SEL

I have replaced:
1. The fuel filter; and,
2. The two fuel pumps; and,
3. The ignition control module; and,
4. spark plugs; and,
5. spark plugs wires; and,
6. cap and rotor; and,
7. engine computer; and,
8. fuel pressure regulator; and,
9. And all vacuum lines;
this was the only car in 40 years, that kicked my A$$,
I decided to remove the engine and put a Diesel in it, because it is such an awesome machine, as I began to remove the head, I found four cylinders cracked, I believe the car was going in to limp mode, it was using coolant, but very little, I did not think it was a problem,
but my advice to you is, have the cooling system checked out.