My previous 1986 300E pinged like mad under load when I did not use premium
My present 1997 420E runs fine on regular fuel and I have never heard it
ping when under load.
I assume the knock sensor on 420E kicks in to retard the ignition. Apart
from decreasing my 0-60 time on acceleration is there any real harm in using
The dealer told me that in the U.S. South there was "bad" regular gas and
hence MB advised using higher octane!!!! The handbook talks about
damage to catalytic converter(? incomplete combustion of gasoline) if
regular fuel is used.
Any feedback appreciated.