Engine Oil Pressure Gauge

Replaced the oil sender unit on 7/12/2010, replaced the wiring harness on 8/28/2010; so I guess it is the gauge and you cannot just replace the gauge itself, I was quoted around $1,000 for all new gauges and that I think is without labor; I guess I will just have to tap it; The car is in very good condition, everthing else has been fixed with 109,000 miles on it; its funny why it can work perfectly for about three weeks in a row and then not show a reading unless you tap on it for a few days and like today works fine; has to be the gauge, unless some other wiring I am not sure about or my mechanic does not understand; might try someone else about the wiring; I want to thank you very much for the reply, very much appreciated. Alan Fradkin 310-920-9847-cell