Hi all,
My 1993 240 sedan has recently had some trouble with the speedometer. It will sometimes work perfectly well, but sometimes, it will wobble, bouncing up and down at about a 10 mph variance, while the car is at constant speed, somewhere below the actual speed of the car. Anyone know what it could be? Thanks in advance.

 

probably failing/leaky capacitors on the circuit board of the speedo.

 

It could possibly be the wiring on the back of the rear differential. The insulation on mine was flaking off, so when I'd hit bumps or be on a bumpy road it'd wobble because the wires would touch. The sensor isn't hard to miss. It's the only thing with wires going to it on the differential. Check the wiring!