Over the last few weeks sometimes I felt that my car didn't have the punch that I expected it to, or recalled experiencing previously. Certainly did not feel like the worlds fastest four door.

It was mostly in cold weather with wet roads but the car was still hooking up fine. The car was warmed through but just barely. Sadly I began to worry if I had made a mistake in purchasing this car as I recall being much more excited with the power delivery in my simpler C63.

Then today, it's warmer outside, and after running some errands and getting the oil temp up to 100C I put it in M, sport suspension + sport mode TC and it is much faster at the top end of the rev range and the shifts noticeably crisper. That 'limp' feeling is gone and the beast is back.

Most of my driving is short trips. Do you think it's possible that the ECU would limit power in cooler conditions before the car is warmed all the way through? Or possibly consider outside ambient temperature?

Any one else experiencing anything like this? Kind of ambiguous I know.

Before warmed up absolutely. Ambient, less likely unless extremely hot or well below freezing.
Temps need to be nominal normal. M3 and old M5 had variable redline when cold, climbing as it warmed. Gearbox temps can lag engine temps by 20-30C in warm up, so needs time.
I've always limited throttle use before I shut down, as turbo turning 150-200k, and nice to have it slow before shut down. I always cringe when people blip throttles and shut down, or cold start and rev crap out of it. Oil is only thing between bearing and housing. Take IR thermometer and point it at turbo housing, or look at EGT. Cause for pause.
HTH.

Ive had the identical experience.

of note-

-Sport handling significantly raises applied power in anything but perfect traction. I *wish* I could have the AMG button switch the active handling/traction control to "Sport".

-Comfort mode seems to make the throttle much (much) less responsive

-If you end up with even slightly poor gas, you'll notice substantially less power until you refill. It doesnt surprise me that this is so... It surprises me I got bad gas. You dont pump your own gas in Oregon; I suspect the guy pushed the wrong button while I wasn't looking. After the fillup, the car noticeably woke up.

It's like that back in NJ, and it drove me crazy having to wait for someone to come over. Many times, I simply pumped the gas myself. At one station in Newark, many attendants were also having lit cigarettes between their teeth while pumping on more than one occasion. I ended up calling the headquarter (Mobil, I think) and lit cigarettes were gone since then.

Same situation on my TurboX... when cold it feels like I only have access to 50% of power. Turbo gage goes in the middle. Then it warms up and gradually the power kicks in. I guess it's a good thing to protect the engine from overworking when cold.

Interesting... thanks for posting. Definitely nice to hear I'm not the only one.

I also wish the TC could be linked to the AMG button.

Also, since you mentioned it, the car 'came back' immediately after a tank of new gas. Interesting observation.

Nothing but shell V-Power or Petro-Canada Super-Net 94 for my toys!

Could it also be the ecu adapting?

Don't need 94 in calgary. You can actually get away with 89.

Are you getting away with 89?

No. I'm just saying that at our altitude, you could.

With crazy DA fluctuations we have, I'd rather be protected and always put a minimum of 91.

I have found this as well lately but I guess record low temps as of late could be the culprit. I need to fill her up in the morning with fresh gas so maybe that may change things. During heavy acceleration do you feel the AWD working? I do but sometimes it seems to pull mainly on the passenger side. Maybe it's the road surface I am on?

I am with you on the AMG button and TC. I feel the AMG button is useless or am I completely missing something. It doesn't set the car to an optimum level of insanity as I was led to believe it would. You still have to select suspension, TC and S,S+ or M??????? Is the button silly or am I?

My car squirms a bit under hard acceleration on uneven pavement or with inconsistent grip between rear tires. Remember it is a fixed torque split, so the computer isn't modulating power if one axle starts to lose traction, it just cuts the power back. So that squirming feeling you get is just the car losing traction briefly before the TC unit cuts the power back... but you notice it in the rear because it gets 2/3rds the power

The AMG button is just a memory button that will apply a pre-set combination of transmission mode and suspension setting. Works the same as your seat settings - pick the two combos you like and then hold down the button until it beeps.

If you want to change the TC setting you need to press it once to get sport, or hold it for 5 seconds to turn it off completely.