I have a big carbon build up around my third injector and when there was a load of water in the gulley and the engine was running there were air bubbles coming up so I know the seal is gone. Going to replace it this week but what I'm wondering is, what issues would this have caused?
Been like it for so long I can't even place when it happened so can't remember if any issues would have been caused by it that I have just got used to.

Would it cause lumpy idle or hesitation on pick up?