I noticed something the other day and I don't think it's normal but I really don't know. I was driving and I was listening for a sound I thought I heard from the engine. So, I floored the accelerator while it was moving for a few seconds.

Obviously, the RPMS went high (up to about 6-7000) However, when I completely let me foot off the gas, the RPMS came down a bit but then stayed stuck at around 5000 RPMs for a few seconds before dropping down to normal. It will consistently do this every time. Is that normal?

I'm pretty sure in my old 2017 gle (or any of my older cars) that if I floored the gas and let my foot off completely, the RPMS would return to normal immediately.

 

Hmmm, might be because the transmission thought you want to overtake or suddenly drive in a sporty manner so it holds gears and therefore stays at higher RPMs.

 

unless you driving over 110 in that thing, it shouldn't be in the 5K on the tac. more like 1900-2200 rpm in 9th gear. is this in Comfort or Sport mode. I'd have it checked out immediately.

 

The velocity at which you press the pedal tells the transmission what you want.
A quick stab indicates that you're looking performance, so it will drop several gears at once, into the performance range, which would be 4500 to 6000 RPM.

That quick stab seems to override any setting, such as Comfort, and the tranny holds the gear --- waiting for your next performance-like input.
After a few seconds, it returns to your chosen setting.

It's normal.

 

This. It was holding the engine in its power range for a little bit in case you wanted power again quickly. You can also get it to downshift and hold for a few seconds by giving the accelerator a quick stab and then returning to your previous pedal position in preparation for a pass.

 

Release the NOS button