I have a 2018 GLE 350 with 50,000 miles. Intermittently, when I stop at a red light or traffic stops moving, I can hear the engine power down, tach goes to zero and when I accelerate it won't go for a few seconds. Then it suddenly accelerates very fast and jerks forward. Yesterday it happened twice when turning across the lane of traffic, so this is definitely getting to be a safety issue. This has happened a couple of times sitting in idling traffic, and when it takes off there is usually a car in front of me. The car has been serviced and maintained regularly and we just had the spark plugs replaced. Any ideas? This is intermittent so we have been unable to get it to replicate during visits to shop.

 

Sounds like the start/stop killed the engine and the engine didn't turn on quick enough when you floored the pedal?