Compression check first. If all the cylinders are good you can move forward. You can look all day at stuff but if a cylinder is down you are way ahead in time wasted. And you truck ain't exactly cramped for space to do this
If a low cylinder rotate till valves are closed then blow air into plug hole and listen to see if it is escaping through intake or exhaust. If a valve is leaking you can hear it. If not then rings or head gasket.
Ticking noise that goes away with rpm sounds like something sticking or pressure related (or both). Sticking or failing lifter maybe.
Also stupid thought but hit your intake manifold with some carb clean at the gaskets to see if there is any vacuum leaks. Dont blow yourself up but your idle will jump if there is a leak. Also a source of a lean pop.
Vacuum check first then eliminate the compression issue. Just my .02
W
