Running rough

Hi We have a 12h teir2 s/n CBK00801 ,that has an intermittent fault within machine starts to run rough, missing and derating with the pressure light on the dash on .
Connecting the computor comes up with a code 164-11 injection actuation pressure , but not all the time can run sweet for ages then it comes on ,shut down wait restart most times ok we fitted a press guage between the senser and block pressure comes up and matches numbers on the computer

Running rough