cyl. balance issue
 

Any suggestions on cylinder balance issues I have 2, 6, and 8 cyl . balance problem I had 2 and 8 for about a week then 6 came in line with them ,,What causes these coads to come up po284 and po266 didn’t get the coad for #6 until today please any ideas ? fuel pressure 70 psi idling. 55 psi floored// ficm checks 48.5 running . I replaced injector harness with no prevail there no air bubbles in fuel bowl wile cranking. What next? HELP. Thanks for any input.

Are these issues out of the blue? How does the truck start/idle/run?

If one injector has o-rings leaking it can cause others to throw codes if they're good too, it will leak combustion into the entire "rail" there and falsely throw codes for other injectors. Or maybe you just have some injectors going bad. How many miles on the truck? What oil do you run? What oil filter? How often do you change your oil/filter? What about fuel filters, what kind do you use? How often are they changed?

totally agree, when it's all in one bank like that and comes on kind of quick it will probably be a loose injector that let combustion pressure into the rail and can be hard to diagnose which cylinder is causing the problem. You can get new Orng kits from the dealer for around $5 a set, get yourself 4 sets and pull all injectors on drivers side and inspect them good, if you have carbon built up on anthing more than the tip you found the cause.