I had an 2005 E55 that I recently sold that was having issues stalling on hot days at freeway speeds after driving aggressively. Fealt like it was starving for fuel then would die, after about 10 mins of sitting it would restart and drive hundreds of miles just fine. I thought the issue was fixed but the new owner just told me it happened again.

Yes, I know Mercedes Crank sensors are garbage, and yes, I already replaced it. Issue is still there. I know the 203s were having fuel pump issues that were causing symptoms like this, do you think i should throw some fuel pumps at it? Dont know any surefire way to diagnose this since it is so intermittant. When it happened last time, i pulled off the fuel rail cover and it had fuel pressure. Maybe it was vapor-locking though? Anyone else see this? BTW, intercooler pump is shot but i dont see it causing the stalling issue.

 

If you have a fuel pressure gauge you can hook it up easily to the fp test port on the fuel rail. It should have a black plastic cap. I think you problem is probably one of the fuel pumps. I believe you have 2 of them you will prob need to pull the back seat and the circular covers then put a stethescope on top of the lids to see if you hear them both running while turning key on. They will run for a few seconds with key on but should run constant while cranking engine...Also, check for trouble codes but often fuel pump failures leave no codes. Hope this helps

 

If you have fuel pressure, stalling can cause by ignition...

You said you replace Crank sensor, oem or aftermarket one..

Your symptom indicate you probably have a crank sensor failing again..