Why Common Rail Nozzle Fail in Vehicle while work good in test bench?

Claim:
We bought the well-known brand CR nozzle. It works fine while testing in test bench. After fitment of injector in vehicle it start properly but 
after a week or so it drop the pickup and starting problem also constantly. then we test it again in test bench the fuel delivery is less.

Causes
According to the description,we can simply judge the problem is the spray hole blocking caused by the dirty diesel.
As we know,common rail nozzle is high precision component located injector.Even tiny impurities can bring the blocking of normal spraying diesel.

Troubleshooting:
Clean the spray holes with special equipment.If you need help,we can help.

Advices:
(1)When you replace one new nozzle,expecially DENSO or BASCOLIN,make sure your diesel fuel is clean
(2)Clean the diesel tube regularly.
(3)Change the filter regularly.