I changed all the o-rings on my injectors a week ago. Yesterday #4 started leaking so I popped the rail off to re-seat. All the injectors came out with the rail and popped out of the manifold as well. One of them the o-ring and the little plastic(?) collar below the o-ring came off and were down in the manifold opening. I was able to get the o-ring but the little collar went through and is gone forever. Do I need to replace that thing? There are no leaks now after reassembly.