After sorting out my electrical issues, inital startup revealed the engine has begun knocking. Now I've driven the truck almost everyday for 5 years with no issues, but it sat for about 3 weeks while I was sorting the electrical problem.

I let it idle for about 20 minutes and the knock smoothed out and went away. For the past couple days I've been driving it, if you even think about getting on it hard the knock returns with a vengeance, and this morning when I checked the oil I didnt push the dipstick in all the way - so on my drive in I was smelling burning oil (NOT normal.) Got to the shop, and saw oil had gushed/sprayed from the dipstick tube.

TL;DR - Engine knocking, truck sat for 3 weeks, oil coming from dipstick, truck has 2 PCV valves not clogged. Ideas? Lifter? Weak oil pump?

 

It needs ONE PCV valve and one breather to feed filtered air.

Hard to say what your 'knock' is without more information.
Does it only happen under load, or will it do it in neutral?

 

It'll do it in park, neutral, acceleration, 700 RPM, 4500 RPM, you name it.