[TJ's GMC]

Well I have no idea what I did but the engine decided to quit knocking all by itself. LITERALLY. I pull all the new plugs and put the old ones back in...still knocks...pull both valve covers to make sure everything is moving and nothing is bent. Has a little more sludge in there than I'd like to see.....Ran it till she got hot and pulled the radiator cap to see if I had a blown head gasket...no bubbles....now it only knocks on deacceleration.....so you rev it and while it comes back down to idle it knocks just a little now....with the old or new plugs. So the plugs aren't the issue. The knocking from deacceleration sounds like a very loose rocker arm but its not. Hard to explain what it sounds like and the camera doesn't help either. I'm starting to think one of the lifters is hanging up a little. Thoughts? Knocks when the engine comes back down to idle..sometimes.