2009 Nissan Sentra - Why does it rev?

Why does my Nissan Sentra rev when starting?

It’s cold and require a nenriched mixture to keep it running which will be corrected as the engine warms up.

Happens in all cars

He has had it for years. It just started doing it.

A bad engine coolant temp sensor to the computer can cause that.

Tester

Thank you… I will tell him to have it tested.