1987 300E. On acceleration there is a vibration between 15 and 20 mph
which feels like going over rumble strips. Light and hard acceleration
produce the same symptom. The vibration seems to get worse as the car
gets driven longer. For instance, when cold, the problem is really not
noticeable. After 45 minutes of driving it is very noticeable. Except
for this vibration, the car accelerates beautifully.
I have recently replaced all of the rear control arms, all 4 coil
springs, a ball joint, a tie-rod end, the steering idler arm bushings
and all 4 tires. I also had a recent alignment. The car runs straight
and smooth as fast as I care to go.
Based on the symptom getting worse as the car is driven longer, my
thought is that this is a rubber part failing. I would appreciate any
thoughts of where to start looking and how to identify whether or not
the various parts are failing.