I have a 1986 300E, and it takes 4-6 seconds to start when the engine is cold ( a long time in my opinion). Also it's exhaust is smelly (not smoke yet an odor that keeps cars at a good distance from me). The Oxygen Sensor light comes on sometimes, and I'm curious if I replace it would it fix the above issues. Also I run 87 Octane in the car. Finally I had the valve seals replaced due to oil consumption a month ago. Thanks in advance! Roy