I have two questions regarding my 89 420 SEL with 131k miles:

1. The transmission seems sluggish when shifting into reverse and drive. When it does shift, it is almost seems to "drop" into gear. I have changed the filter, gasket and fluid recently and didn't notice anything irregular. It did not help to solve the problem.

2. The car does not want to start right away. Once it does start, it will idle roughly for approximately a minute unless the gas peddle is depressed. Ambient temperature and engine temperature (whether the car has sat for a long or short period of time) do not seem to help or hinder this problem. I have changed the following items: spark plugs and wire set, fuel pump relay, oxygen sensor, fuel filter, distributor cap and rotor and air filters.

Any suggestions?

As for the tranny, it is almost considered "normal" for it to take a second or two to go into gear. It does not mean your transmission is going bad, as long as it shifts ok.

If your screen name is referring to the band D-Train, good choice

I may stand corrected on what I'm about to say, but I seem to recall reading here that if the O2 sensor is changed, fuel mgt. may need to be adjusted. It might not hurt to hire a seasoned MB pro to look over fuel/engine mgt.