The 2013 Mercedes S550 W221 series car has a powerful engine known as the M278. After a while the gas pedal will not feel as responsive as it once did when the car was new. I'll tell you a few minor repairs you can do yourself that will help your Mercedes get excellent throttle response back. In other words, if you barely press the gas pedal and you don't get pushed back in the seat, its a combination of a few different things that are getting a little worn out and once you replace these things your M278 is going to become very happy again and you'll experience the true torque of this car as if it were new.
Use LOCTITE SF 7200 for removing old gasket material from the face of where your cam timing chain covers bolt to the engine and then clean metal surface with LOCTITE SF 7063 before putting new gasket material on. Don't use sand paper or a scraper, I'd recommend using a cotton towel and saturate it with the LOCTITE SF 7200 then keep working it on the metal until all the old gasket has vanished.
Get Bosch Oxygen Sensors from Napa Auto Parts, they are the same exact ones Mercedes sells at their parts counter as Bosch makes them for Mercedes. The Cam Magnets and Cam Sensors, I'd get them from a Mercedes dealership parts counter with your VIN #.
Remember, this is a high performance engine which performs at its best with high octane gas, so I also highly recommend you use Chevron Premium gas only. It'll keep your engine clean and running its best. I know, premium at Chevron is kind of pricy right now, but if you use cheaper gas from anywhere else, the money you save over a year or more will end up being spent anyway on repairs to your fuel system. Great engines don't run well on cheap gas.
