Hi the code you have is for low fuel pressure which is normally one of the pumps but being as you have changed them that rules them out I think the noise you have is the fuel pressure solenoid on the fuel rail these rattle when worn and won't hold the pressure in the fuel rail.
Steve.
FOR SALE £10,000 – Collection Lincoln LN3
Audi Coupe 2.0E
1995 M Registration
1984 cc
Blue
Petrol
1 Owner (ex demo)
Mileage at 08.07.23 – 81047
MOT to 24.08.23
Service History – Partial
Garaged
No accidents
Purchased new as an ex demo
One wing replaced with genuine part due to a small amount of corrosion.
Immaculate