Signature 600 chuffing

[Creek]

Just following up. As I said took it to Volvo dealer (mistake I know) they found no problems. Drove it 10k miles. No change so took it to Kenworth dealer here close by. They checked overhead again and found some valves that needed minor adjustments. Nothing major. They said they did a cylinder imbalance test. It passed. An injector cut out test. It passed with one injector being weak and borderline failure. They said drive it. And yes I could still hear the miss. So I drove it another 6-7k. Then I took it to a guy in High Point NC that has great reviews. He said it sounded like injector knock. But it is hard to determine which injector, but from what I read on here it can be done. Anyway, the ReCon engine has 450k and to replace all six injectors is about 4500 according to the shop in High Point. What does injector knock sound like?
Do I replace all 6? Go to different shop? Invest in Insite? Go to Cummins dealer? I’m 66 and maybe need a rebuild myself. :sleepy: