Low fuel pressure faults on '08 A4

I've had a low fuel pressure fault going on and off periodically for a few months now. Originally had the code checked but it had already gone off be the time I made it into the shop. They were reluctant to do any work with the light off and the car running fine so I put it off until my next scheduled maintenance. Light continued to go on and off randomly, can't seem to pick up any pattern



Took it back in and here is what they tested:

"Monitored readings from fuel pressure sensor. Found readings fluctuate out specification. Suspect sensor is faulty or fuel pressure is not correct. Tested operation of fuel pressure sensor and it's OK. Performed output test of fuel pump and it's OK. Found fuel pressure is now within specification. Symptom is intermittent so tests are so far inconclusive."



Anyone experienced something similar? Any ideas? I'm reluctant to just replace the sensor, or at least not until I know a little more.



Codes are:

1) "Low pressure, fuel pressure regulation" - P129 E

2) "Low Pressure fuel regulation" - P310 B



Thanks!!