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. 

 

Note:  A professional diagnosis is recommended to ensure the rail pressure sensor is the cause of your issues. If mis-diagnosed and the rail pressure sensor does not fix your issue it cannot be returned once it has been installed.