The analog senders (oil pressure, coolant temp, and maybe others) don't directly control the dash gauges. Instead, the senders are used to ultimately display info on the dash through the vehicle ECM. So... a potential list for a problem of an erratic display of oil pressure or coolant temp is more complicated... The sender, the wiring from the sender to the ECM, the ECM itself, the wiring/connectors from the ECM to the individual dash gauges, and of course the instrument panel gauge cluster generally are all potential causes of an erratic display.