Bama2door

I'm having a problem with my '02 6.0. It has a misfire in cylinder 4 & 6 and idles decent but has no power over 20% throttle. I've changed injectors around, spark plugs, coil packs and still nothing. We also took off the valve cover to do a visual inspection and i turned it over for a second and it didn't seem like any of the springs were busted, but I hear it is hard to see at times. It has progressively gotten worse over time. At first it started as a top end mis and it would be kind of sluggish in higher rpm. It got pretty bad, but at the time thought it was the trans going so i replaced it with one I had waiting to go in and after startup it seemed the same if not worse. Brand new torque converter too. Any ideas?

Also I was at Atomic's house trying to see if we could figure out the deal and when I was driving home I would hear a knocking noise when it would get about 20% throttle. Should I get some new springs and try them out? I'm running yellow ls6 springs and have a TR224, could that cam possibly have been to much lift for those springs to break them? Springs probably have 5k miles on them. I'm hoping it's nothing major internally, but I am all out of ideas and need y'alls help/opinion

SlickSierra

iTrader: (4)

timing chain?

DR132

is your compression good?

budhayes3

iTrader: (19)

+1, check compression first. Misfires in 2 cylinders side by side can often be an indication of a blown head gasket or cracked head...

Bama2door

Cool thanks for the ideas guys. I am going to pull the springs off today and check to see if any look broken, also going to take the timing cover off to check the chain. I haven't seen any coolant leaking out of the heads and the oil is not milky at all, I would be really surprised it it was heads/head gasket bc the gaskets are basically brand new...

Bama2door

I took the 10 bolts off the timing cover and left the balancer on so I could just peek in to see if the chain was messed up or loose, but all seemed ok.

Going to check the springs tomorrow and I need to check compression

Atomic

iTrader: (42)

indigo s10

iTrader: (2)

I had this problem with #2 and #6. #2 Valve guide seal was bad, causing lower compression and a random misfire.