Mate I've just been through this exact same problem over the last few months with the bosch 023 (040 big bro). First time pump last 3months but got noisier and noiser. Must've got a bad batch of fuel or something because it started leaning out big time and groaning badly. Fuel pressure dropped 2 bar. Took out the pump and the entire screen was filled with minuscule particles. Bought a new 023 whilst cleaning the old one and testing. Fixed the problem for about 1.5months then did the same thing. Exact same problem but I have suspicion my 'Submersible fuel line' was not what it was supposed to be. Replaced old pump, Was fine for 3 days then the same thing happened. Long story short. The bosch intake fuel pumps are incredibly sensitive to debris. Seeing as they only have a screen mesh and no removable filter they are restricted to a flat surface area that once blocked, cannot allow sufficient fuel to be delivererd to the system. If you have a fuel pressure regulator with a gauge, check your current pressure at idle. Solution - Install a walbro. Your current power figure could get by with a 255lph but if you plan on chasing more power (I have the same turbo @ 300rwkw) go for the 400lph to future proof. They're smaller, more efficient, easier to fit and have a larger surface area of pick up due to the removable filter sock. Edit: Forgot to mention - I only fitted the walbro 400lph pump on Tuesday but the pump is dead quite, fuel pressure is up around 3bar idle (vacuum off) and it's the smoothest it's been in months. Will be pulling out the pump in a few months time to asses the sock as I still believe there's debris in my tank.