Had my 5 week old MCS into the dealer last week. It had 1200 miles then. It would lug down about 40 in the regular mode and I had the popping in Sport mode. They said the popping is normal, they could not find anything wrong for the other after 2 and 1/2 hours at the dealers. Now 3 days later at 1345 miles, I have a Low Vibration sound when slowing down and applying the brakes. The sound keeps going for a few seconds even after the car is completely stopped. I noticed it yesterday when pulling into the garage, but is noticeable with the windows down when driving slow. Sounds like the passenger side engine compartment.
Any ideas? I am calling the service dept again tomorrow.

 

Is it an auto?

 

Yes it is.

 

Might be an issue with your torque converter... My wife's '02 accord makes that noise when it's not moving. Does putting it in nuetral make the noise stop or change it in anyway?

 

does it ever start dipping up and down in the idles? With my NM torque arm insert + tune on JCW, the idle sometimes searches up and down. When it dips to low, you can feel and hear a vibration before it jumps back up. Take a little while for my car to 'warm p' and find idle.

Just a thought, watch the RPMs.

 

I still hear it in neutral but it goes away. When I pull forward or reverse the car the sound is loud but dissipates quickly when you depress the brake all the way.

 

Went to the dealer. The noise was caused by a turbo heat shield that was loose. They said it was because my car was new and that it vibrated loose. My husband wondered if they forgot to tighten it down after it was in the dealer last week. Either way, that is the answer and it was a quick fix. Whewwwwww.