So when my 6.9 leaked all the fuel in the crankcase after the IP failed, I had a tick when I put my new IP and injectors on. I was fearing my oil thinned out and I ruined something and had so much fuel over the top of the engine from changing everything over I didn't see my one injector leaking past the body of the injector up from the threads. Injector ended up being defective and was causing my tick.
I found it by wiring a toggle to the cold advance, and turning that on while going down the road "making" the truck tick and throwing it to switch the timing and it really made my knock better when I turned it on. Then I started looking the engine over better after drying it up and found my culprit.
I guess it's just another version of shutting the truck off going down the road, I had already tried my weird method before someone suggested that on here. Not sure if my test "really" works, but man I still remember the sound going away when I turned the cold advance on and my engine I though I ruined turned out to be fine. 20k miles later now and it's still chugging along.