Firstly I'd pull the injectors and test them.
Don't write them off immediately.
Test them correctly.
Write down the results. Ie break pressure pressure hold, and spray pattern, and stuccato effect.
If you have one or two that are playing up, disassemble and clean.
Use a bycycle spoke snipped at an angle and end flattened with a hammer to gently tease out any dirt. Use an appropriately sized sewing needle through hole.
If any pintle needles are too loose in their holders, then this will show up with dribbling out of the offtakes, generally there should be such a small leakage that you will see nothing. Check that needle barely [slowly] drops into nozzle of it's own accord.
Give up with them if the last paragraph fails. They will function but won't pass the same fuel as the 'better' ones...