Replace oil Pump?

172K mi. on my 2000. When driving at highway speeds, oil pressure is fine, but when idling oil pressure drops too low. "check guages" light comes on sometimes, but throttling up picks up the pressure immediately. After checking oil pressure with an external guage, determined oil pressure sensor and dash guage was accurate. Planning to change the oil pump this weekend. Did I miss anything?

I would replace the oil pressure sending unit first they are known to leak and fail

Yes, do the cheap easy stuff first

Seriously do the cheap easy stuff first..
Strange, my sending unit went out around 170 K, very strange.

IT was 15 to 20 to get a new one.