My car is stalling

If the gauge drops and there is no ticking or knocking from the engine, chances are there is not an oil pressure issue, but rather a bad oil pressure switch. What I would suggest is to rent a mechanical gauge. All you do is remove the electronic one on the engine and screw in the mechanical one. Start the engine and see how much pressure the gauge reads. At an idle, it should be at least 15 psi and then increase as you rev the engine. Just to make you aware, often times the switch will leak allowing pressure to be released, showing a false reading. Do that and let me know what you find. Remember, if there is no knocking or ticking from the engine, chances are what I am telling you is correct.