I have also read that when one injector fails, the rest wont be to far behind it. The power balance test also showed a slight RPM increase in the #8 cylinder. But turning that injector off with the engine running made a big difference in the way it ran. It will be interesting to see if #8 is the next injector to fail. The truck is an 04 with a 6.0 in it. I did this test on a friends 06 and the line was flat. If #8 is the next one to fail, that would tell me the power balance test is a good indication of which injectors are on their way out. Only time will tell.