190e speedometer irratic?
 

My 88 190e 2.3 speedometer is frequently irratic. Usually it functions normally. Occasionally the speed indicated is 2-3 times actual. Wish the car really could accelerate like that! Any ideas what is causing this?

It's likely one of two causes. First, you could have a failing speedometer cable, which attaches to the transmission at one end and to the back of the speedometer. If the cable is binding, stretched, or broken, erratic needle behavior will result. Some have suggested lubrication of the cable, but that really doesn't work and in the long run, will eventually kill the cable faster. Replacement is the real cure.

The other suspect would be a failure in the VDO speedometer works. Luckily, there seems to be no shortage of inexpensive 190E instrument clusters for sale. If it is the cluster and you do need to replace one, make sure you get the proper one for your car, since the clusters did change by engine size and year.