I put a new fuel pressure sensor in 4 days ago ran fine. Now it is coding fuel pressure sensor low pressure but I do not hear the fuel pump buzz at startup is it the fuel pump?
It might be the fuel pump. Something you can replace before your fuel pump is the fuel filter. If this becomes clogged, it can give a lower pressure at the fuel rails and could trigger a low fuel pressure code to your ECM. If this doesn't work for you, then I'd check the fuel pump. The easiest way to tell is to put a fuel pressure tester at the fuel rail to see what it comes up to when you turn the key on. Most current vehicles with fuel injection has a test port which is a Schraeder valve (same basic thing as what holds air in your tires) on it (not to be confused with either of the A/C ports). I don't know exactly what the fuel pressure should be on your vehicle, but believe it should be around 43psi.
You have changed the fuel pressure sensor, and you have a low fuel pressure reading. The fuel pressure sensor reports the fuel pressure in the system. This pressure is controlled by the fuel pressure regulator. You will need to have a fuel pressue test which at idle should be 3.7-3.9 bar. A low reading will point at the fuel pressure regulator on the fuel rail.