Oil Pressure Gauge Question

[48richard]

My truck has both an oil pressure gauge and an oil pressure warning light (I put in a Camaro tach and hooked up the oil light in it). The gauge and the light are connected to the same port in the block with a T fitting. Lately when I start the engine the oil light goes out as soon as I start to crank the engine, but the gauge registers zero for a couple of seconds after the engine starts, and then very rapidly goes up to a normal reading. Its a jerky motion, like something is "unsticking". Is there something internal to the engine/oil pump that could cause this, or am I looking at a gauge/pipe problem?

Thanks,
Richard