Bboble4k

I have had a persistent check engine light appearing for a fault code P310B. VagCom indicates that the fault is thrown at a near or identical ambient and coolant temperature which would indicate this to be a cold start issue only. I am able to verify that the engine is slightly rough and sluggish to start up to indicate low fuel pressure. Block 103 is indicating a pressure of 4.5-5.5 bar on most cold starts performed recently and doesn't appear to drop much. Fuel pressure then remains around 5 bar at idle. The low fuel pressure sensor has been replaced by the K revision and a new fuel filter has been fitted. At this point I feel I ether have a bad "new" sensor, there is a check valve in the fuel system allowing pressure not to be held, or the pump is not priming long enough to build adequate pressure before start up(yes, I turn the key to the on position and allow the fuel pump to prime fully before cranking). Is there an adaption to allow the fuel pump to build a higher pressure or is that going to just mask a possibly more severe problem?

Vehicle: 05.5 A4 2.0T
Any further thoughts or advice is welcomed...


Thanks in advance