I went to Kragen to replace my air filter, and they didn't have the filter I wanted (regular OEM), so they sold me a K&N filter. A few days later the Check Engine light came on and my car stalled, not starting until I put in a fuel filter in the gas tank. Even then the acceleration was slow. I then tested the engine with the OBDII tester, and it said there was a problem with the oxygen sensor, so I took it in to my mechanic. To my utter horror, he said I need $2,000 worth of work on the engine because of the fact that the air intake was too strong for this type of oiled air filter. Is this a well-known issue? Is K&N aware of this? Is Mercedes aware of this?