Sticky injectors?? The nozzles in the multi are the pintle type. I takes a given pressure..14,000 or so, to un seat the pintles in the nozzle. They are a normally closed. If they were sticking, i guess that would mean they would open late or stay open too long. If they were opening too late, you'd most likely have white smoke and low power.. too late of an injection time, or if they stayed open too long, black smoke, low power, dying..if the pintle stays open too long, the cylinder pressures overcome the fuel pressures and force the compression back into the fuel system. BUT, the Bosch fuel systems can have a dribbling injector..there is a specific test for this..If this is the issue, the engine will smoke black all the time and have a noise kind of like a marble rolling around in the engine..it's kind of a cool sound. If this is the issue, you can short it out by losening the injector line from each cylinder and giving it a quick blip on the throttle. The noise/smoke will be gone when you locate the failed injector.
Not that it means anything, and I don't wanna sound like a donkey, but, I have 20 years experience on Bosch fuel systems. Never heard of a sticking injector on a Bosch system, but, you learn something new, every day!