Are you seeing intermittent rail pressure fluctuations that are causing running issues? The rail pressure sensor may be the root cause.

 

The fuel pressure sensor is a crucial part of the high pressure fuel system. It effectively measures fuel pressure allowing for proper pressure control from the ECU. A faulty or failing sensor can cause serious running issues and potential system failure due to over pressure. If the connector is broken or cracked, water could be introduced to the terminals also causing incorrect information to be relayed back to the ECU.