Instrument panel problem E30 1986 325 coupe

Hello everyone, yes I have another problem for you fine individuals to solve for me again! The instrument gauges on my dash broad are going crazy. First the mpg gauge in my tachometer will stick, than the speedometer will drop out 60mph to 0mph and not come back up to 60mph again. Sometimes the speedometer works fine and the tachometer will drop out and the speedometer is fine. After the instrument panel drops out and I ride over a bump, every gauge sterts working fine again. This happens a lot more in the winter than summer. Oh! If I stop at a stop light and turn the engine off. Before the light turns green again, I will restart the engine and everything is fine again for a bit. Do I need to change the control unit or a computer module or is it something else? Thanks if someone would be able to help!

Start by checking and cleaning all the plugs going to the rear of the cluster.

also grounding nuts on the back of the cluster, and also check the connectors are on securely. on euro cars there is a black tab you have to slide out before the plug comes out, i assume USA cars are the same. make sure the black clips are still present.

definately a gauge error, the senders are completely unrelated, the MPG and tacho run directly off the ECU, the speedo runs off a sensor on the diff.