Q&A

So far what I've done erase codes the I took coil packs 5,6,7 and swapped them with 2,3,4 re run truck and that didn't change code still come up the same. I then disconnected all 4 injectors wires on the faulty bank so now the engine is really running rough, then I would plug in one, you can hear the difference when plugged in (smoothens out) then I unplug that one and do the next, same thing and so on. In other words I plug it in then remove it and do the next in line etc. I have noticed with all 8 back in run and it sounds like its backfiring through the throttle body so I took the air horn off to see what I can see. The throttle butterfly flops back and forth, and putting you hand over the opening you can feel the back pulse of air.

CHECK COMPRESSION ON MISFIREING CYLINDERS. "IF"OK,} ALSO CHECK FOR VACUUM LEAK THAT WOULD AFFECT
THAT BANK. (RH,PASS. SIDE) CORRECT?

Feeling a "back pulse of air" makes me believe that the spark plugs are firing when they should not, when the intake valve is open for example. But, given that you have this problem with multiple cylinders, on the same bank ,I would conclude that the issue is something that all of those cylinders have in common(valve train, timing, etc.) I'd go with Wetry's response on the compression check as HE tends to be correct. If you find lean/rich or fuel trim codes then a smoke test for air leaks would also be appropriate.

I'm thinking intake manifold leaking. BUT the butterfly bouncing makes me think timing problem.unfortunately , I don't remember how bad the 'triton' engines are for access to check the lower portion with spray. Is wetry usually right because he types in BIG PRINT or is that just to help me see it better? Did the rough running come on gradually or was it pretty sudden? That info may also eliminate certain things.

Well I must confess I'm a mechanic in a remote logging camp and I work on the equipment yarders, log loader etc. Pickups with electronic engines I know nothing about. As to what happens before they fail I'm in the dark. The common response is ; This piece of crap doesn't run, so I get to figure out what's wrong. On the equipment it's quite easy I'll jump and run it to figure it out. It seems common on all of our pickups that the emission system doesn't work due to the fact that the branches they drive over rips all the wiring off. This truck oddly enough has it all intact. I finally received the spark plugs I ordered. This is the second time as the first set did not even remotely look like the plugs I took out. I will keep you all informed after I install them this morning. Thank you for all the advice to date. Pat