I have a 2001 SLK that continues to have problems with its 02 sensor and mass air flow sensor.  At least every two months the 'Check Engine Light' comes on and the performance of the car reduces until once it broke down when I waited a week to bring it to the dealer...which is an hour round trip from my home.  If the car were not under warranty each trip to the shop would have cost me $743.  Unfortunately, this car has been a dissapointment to me, and I cannot wait until my lease is up and I am sorry for whomever will own it next....if anyone else has had similar problems please post.

Liz,

You were SMART to lease.  I paid cash for my new 2001 SLK230....what a waste of money!