I have experienced recurrent but intermittent issues with the transmission/acceleration of my mercedes glc 300 2017. today, after i went up and then downhill, the car slowed dramatically on its own. when i pushed the gas pedal to the floor, the car did not respond immediately. after several seconds, the car started to accelerate. in the meantime, i was worried i would be rear-ended by traffic behind me. i have had similar problems in this same spot (which i drive nearly daily) in the past, suggesting going over the hill has something to do with it (e.g., once, in this spot, when my daughter was in the car with me, the car jerked so strongly when it started to go that my daughter though we were indeed rear ended). although this spot most often reveals the problem, the issue has happened on flat areas as well. for instance, pulling out of a shopping center, i similarly found the accelerator non responsive. driving my daughter to tennis one day, the car repeatedly jerked dramatically when shifting, primarily in 2nd and 3rd. generally, the issues seem to happen most frequently in these gears. although the transmission seems to consistently take longer to shift in these gears, the more dramatic problems do not happen daily, making it hard to trouble shoot (when i took it to my dealer, they ran their computer tests, and could not detect any problems). i am worried, though, that i will eventually be rear ended or otherwise have this problem lead to an accident. i have seen some other reports of this issue in online forums, and hope nhtsa can check into or at least track it.