Flicker oil pressure gauge

Hello I have a ford ranger 2000 3.0 manual transmission and for the past months everytime I put my car on idle at a stop light the oil pressure gauge just goes wild. It is getting worst and now the car will crank but won’t start until I press on the gas paddle. The gauge goes up and down only when the car is in idle. Any suggestions.

Thanks

Get your oil pressure checked by a mechanic with a mechanical oil pressure guauge.