My '91 300E has started to have a rough idle recently. I just checked the plugs and it's obviously running rich.

The car has 65K on it. I have to take it in to have some work done so I guess I'll have them replace the 02 sensor. Is there anything that needs to be checked or adjusted when the sensor is changed on this vehicle?

BTW, I've been looking at buying a new E-Class so putting a few hundred into my pristine 300E is peanuts compared to buying a new car. The difference in license plates here in Arizona is about $700 between my 300E and a new E320.

Thanks in advance,
Bud