Code 7 is the rear crank position (EZL) sensor, replace it if it has thrown that code. The wire degrades over time and the signal gets less clear to the computer, causing starting issues and random stalls. I had the same thing happen on my 300E...it died in traffic and gave code 7....replaced the sensor....its been 4 months with 0 issues.

There cannot be a "missing" signal from the EZL sensor, the car will not run at all without signal from it.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)