Fuel Delivery problems.

[C. Martinez]

The model is a 1988 260E.
The problem is that first the car would run out of fuel @ a little less than a quarter of a tank then progressed to a littlte less than half a tank. Now, I have come to the conclusion that it does not run out of fuel, something is going on that makes my vehichle stall. It stalls and at times has taken hours to start back up, this last time it had nearly a full tank and stalled out on the highway at a speed of about 75mph. I dont want to put my hands into it unless I have some direction, I am mechanically inclined but have never worked on a Mercedes (My first MB). I was going to buy the fuel pump then found out on the Net, it costs $220 and it might have two of them.

I guess I need advice on this starting at: Is it common for the pump/s to go bad. To do the MB tech experts think it is something else besides the pump, and is/are the pumps even located in the gas tank?
Thanks Alot all advice will be appreciated