Just to make sure everyone knows the time line here Oct 2016: hearing the nasty sounds of detonation, I start trouble shooting. 1) No check engine light, code scanner shows no codes 2) Understanding that a lean situation is unlikely with no code, check fuel pressure anyway, fuel pressure is within specs. 3) Pull plugs, they all look fine, replace plugs anyway. 4) I have a new set of injectors sitting on the shelf, and though my logical mind says there is no call for it, I install the new set anyway, (and keep the perfectly fine old ones as spares). 5) To this point there is no change, truck is still pinging and rattling. 6) Scope the cylinder bores, nothing notable observed. 7) Start believing what I already know; its not a fuel mixture problem 8) Start leaning towards a cam/valve timing issue and start getting smart on how the system works 9) Could be timing chain, cam phaser, tensioner, or the variable timing solenoid. I rule out the chains and tensors, leaving the phasers and timing solenoid. 10) This is the point where the Sea Foam was recommended. 11) Thought about it for a day or two. The best mechanic I know, with over 45 years of experience, recommended it. The motor has (had) over 130,000 hard miles on it, and if I crack it open, I'm not going to put it back together without a complete rebuild. So I sack-up and add 1.5 oz per quart (10.5 oz total) with an oil change, 5w-20 Mobil 1. That was a year ago. The truck now has 148,000 miles on it, 10k+ after the Sea Foam, including an Alaskan winter, and no detonation since. So, you can sit there reading the same regurgitated tribal knowledge, or you can believe me. I did the experiment, the sky didn't fall, and my well maintained, high mileage 5.4 4-valve is still humming along. An that's all I have to say about that.