Gonna bring this back on track....
So my tick/chug/rattle/buzz, i.e. marbles in a can noise still occurs more often than not. Went to run some errands yesterday. Did it the whole time for the first two stops. Ran into a store for 5 minutes, started my truck back up, and no noise for the 5 mile trip home. Started it this morning, same noise again.
When I can hear the marbles in a can while driving, I also have a buzzing sound that accompanies it. I always get both, or neither so I assume they are basically the same thing. I can hear the buzzing when the truck is parked, most audible at 2000rpm. So I did an experiment today. Revved it up in the driveway to 2000rpm, and turned the wheels from lock to lock. At full turn to the left, the noise when away. Turn it back any at all, buzz comes back. Had my wife do the revving and turned with my head under the hood and couldn't hear any difference.
I am no further along in diagnosing the cause or the repair, but it seems more and more like it has to be something rattling. People have replaced the full exhaust and still have the sound, so it isn't that. Fuel feed line TSB didn't fix mine or anyone elses. My engine runs fine, and the sound is intermittent, so I doubt it is the engine. Turns and bumps can initiate, or stop the sound.
Someone please figure this out!