2008 Silvarado 1/2 ton oil sending unit problem.
 

This truck has 175,000 miles on it, I have had no problems with this before but now the check engine light and the oil emergency light comes on while I'm driving. The engine is getting oil! I stop and check the oil, good oil plenty of it. NO strange engine noise or clattering... Sounds like it always does. I drove it like this with the warning ding ding noise going for a solid 200 miles no problems. I now have had the oil sending unit changed out and it did not solve the problem. It will go along fine at highway speeds for about an hour and then it starts doing this. If I pull over, turn off the key and then restart the car in a few seconds, everything resets and we're back to normal. Anyone have a thought on this?

Possibly a problem with the wire or connector plug to the switch.

Was the screen under the sending unit also removed and replaced? There's a TSB for this also we're old oil and filter can cause this as well. Changing the oil and filter may fix iit.