Voltmeter and Oil Pressure gauge not working

The likely cause of this is a cluster issue.

Both of these gauges are just a display that the cluster receives the data from the PCM via what is called a bus message.

Here is a guide that will help with this:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

So, if you have two separate gauges that are not displaying correctly then it is likely the cluster. However, the best thing to do is check for codes and see if we have any sensor issues.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

It is a chance that we have two different sensor issues so let's start with this and go from there.

Thanks