Low oil pressure

I live in Chicago; I have a 1999 Ford Ranger. Now that the weather has gotten cold, the oil pressure gage doesn’t budge when I start the truck. The engine sounds normal. After driving between 1/2 mile to 1 mile, the gage kicks up instantly to the normal pressure reading.

Do I have an oil pressure problem or just a faulty gage? Note: The oil level is fine and there are no leaks and no burning oil.

Replace the oil-pressure sender, usually located near the oil filter…

You don’t really have a gauge and a sender. You have a low oil pressure switch and and indicator that has only two readings, zero and half-way up. It’s really just an oil pressure light that is less reliable.
Does you check gauges light come on and stay on when this happens? If so, then your sender/switch is probably bad. If not, then it’s the gauge on the dash. To fix that is probably more expensive than it is worth. You could always put in an aftermarket oil pressure gauge. Then you would get true oil pressure readings.