Why would my oil pressure light stay on even when the engine is warmed? on 1997 Dodge Ram 1500

The oil pressure gauge goes to its normal setting, but the warning light continues to stay on. I just had the whole top half of my engine fixed, oil used to leak and no longer does. The light still comes on.

Asked by for the 1997 Dodge Ram 1500
During the repair the sensor may not have been plugged back in or the sensor is faulty and needs replaced. Another possibility is that the oil pump could be failing. Why did you have the whole top half of engine fixed for? What was the leak?
There was a rattling noise coming from my engine, there isn't one anymore. The oil was leaking into the fuel lines and out of the engine, also there was antifreeze leaking out of the top of the engine. Every one of those is fixed now. The only issue is that the light will come on and stay on. It started doing that long before the engine was fixed. Also the sensor is new, and after is was replaced the light wasn't an issue. The light stayed off for a long time, then one day came on and stayed on. The gauge is normal between 37-40.
Get the check engine code read for free at a parts store and repost the result on here.
Now there is another issue, the truck is idling very high when it starts and doesn't kick down until you put it in gear?