I agree totally. I watch engine oil pressure, if it was a rod or main bearing the oil pressure at idle would be lower than the 25 psi my engine oil pressure gauge is indicating, This is more like a hollow thumping sound. It is simply annoying. If I had access to a lift which could support the truck I would be under it and narrow down the “thump”. It is the only negative I have about the truck, so much so, that if it was present on day one of the sale, I would have walked !!There is no way that is a valve, rocker arm, lifter noise. The only time that I heard a similar sound was my 68 GTO when it spun a rod bearing. It is not a rod because the noise would increase while increasing and decreasing RPM from idle. Mine sounds to me like a single stage air compressor running in the back ground in time with the engine RPM. It is driving me nuts but I am skeered to death to have some Ace mechanic tearing things apart on a hope or a maybe or just a simple I duh no!!! It is a more than good chance that the result will be a permanent screw up that, if your lucky, toasts the entire mill before the warranty is over!!!