My wife's 1995 C280 with 72,000 miles has developed two problems as follows:

1. When driving at highway speed (65 mph) the engine sometimes develops a miss in one cylinder. The computer must detect this miss and, I believe, must shut down the fuel injector to this cylinder since when you stop the engine and restart it everything is ok. Also, when started cold and only driven for a short distance and restarted, it also has a "miss" for 10-15 seconds. This weekend it tripped the check engine light and I guess I will need to take it to MB to have it checked out. At 69,000 miles the check engine light came on and the computer indicated a "miss" and also a bad temperature sensor. The temp sensor was replaced along with the air mass sensor which the mechanic indicated was getting "sluggish." Evidently, there is also something else that needs attention. Any thoughts?

2. At speeds of 68 mph and above, there is a vibration that is felt in the steering wheel. Thought this might be wheel inbalance so I had the wheels rebalanced (which were not that far out of balance it turned out) but still have the vibration. I have heard there is a shock absorber on the steering column and was wondering if this could be causing the problem? The car had an alignment at 60,000 miles. Any other parts that would cause this problem at this mileage/age?