Help 300e Engine Stall Problem
 

1991 300e 4 Matic With 157000 Miles
Starts Idles & Runs Great But Once Every
Couple Days It Will Stall And Not Start Back Up For About 10 Minutes
Then It Will Run Just Fine Again

This Only Seems To Happen After The Car Has Been Running For A Long Time

Fuel Relay??? This just happened to my 300E. Does it randomly shut off while you're driving? That's what mine did for a week, then it just stopped turning on when I parked, I always ended up waiting 15-20min before starting it.
Good Luck

You might also want to check the ignition distributor. Had similar problems and found the cause here.