HelloCustomer here is some instructions and please reply if you have any questions: I wrote all this before you posted your second post the socket which is a GM special tool that you may be able to get a hold of at a parts or tool store or a snap-on or mac dealer. The socket is just a special thinwall socket I believe.
Engine Oil Pressure Sensor and/or Switch Replacement
J 41712 Oil Pressure Switch Socket
Important: Clean the area around the oil pressure sensor. Do not allow debris to enter the engine.
Important: Note the alignment of the engine oil pressure sensor fitting prior to removal.
Notice: Refer to Fastener Notice in the Preface section.
Tighten Tighten the sensor to 30 N·m (22 lb ft).
I think Jay must have misread your engine size. The 5.3L engine has not distributor. The sensor is located in the top back of the intake manifold. He is correct that there is a specific socket for the removal of the sensor, however, most part stores will rent or loan this to you. Below is a picture. If you choose to replace it, you should only need to remove the top engine cover and lay across the engine. It usually takes me 15 mins to change the sensor. The flat rate time to change the sensor is 0.6 with a part cost of about 80.00. This would mean the job would cost you 150. May I ask what the gauge is doing that you are wanting to replace the sensor?