Our E420 has only about 75K miles. The check engine/electronic light came on and the dealer's mechanic said I'd need to replace left and right oxygen sensors for $600.


After replacing those they told me that there was carbon build up in the air injection ports and that it was ~ $900 in parts and ~$4100 in labor to remove the cylinder heads and clean out the ports. While $900 sounds high for gaskets and connectors, $4100 in labor sounds real high.


Has anyone else ever encountered this type of problem on a car with so little miles? Any advice on alternatives that might be more reasonable?

Thanks for any information.