2011 Ram 1500 w/5.7L cylinder 5 misfire

So I’m having a fun day trying to figure out why I have a cylinder 5 misfire on a 2011 Ram 1500 with a 5.7l. Compression is good, good coil and plugs, no intake leaks, vacuum test tells me valve sprigs are good, and solid cam and crank signals, also a good injector balance test. Then I saw the waveform of coil and injector and wondered why injector is spraying fuel at the same time the spark takes place. Truck runs good until the PCM turns coil and injector off at 55mph.

Valve spring issues don't always show at idle. Did you check vac gauge reading for fluctuating needle at higher rpm?
Those were also prone for lifter failures.

how are fuel trims?, should be lean and cause a positive fuel trim on the misfiring bank.

I did and it stayed steady. Leaning toward a PCM because I can monitor a consistent misfire even though it is not misfiring. noticeable rpm drop when I disconnect the 0fuel injector.

Running compression did make it stick out. 80 psi on cylinder 3 and only 45 on cylinder 5.

That kind of injector timing isn't unusual, in my experience. You'd think it'd fire on the intake stroke, right? But few do. My car fires the injector during the exhaust stroke. :silly:

Definitely pursue the difference in running compression. With those numbers, and the misfire you're describing, leads me to think about worn cam lobes.