Same here, 164k owned since new.. all oil/filter changes well within recommended. Diesel Power added in exacting amounts every tank, BP Ultimate fuel used almost exclusively - if not, premium diesel... and only twice - standard truck diesel. Toyota fuel injector cleaner added every 20,000 km's. Currently up north with 2.5 tonne van. Had injector values read at St. George.... technician reported them all "within spec"... and told me there was nothing to worry about - "normal diesel fuel knock". Was not offered written injector values.... Had motor tested again Charters Towers... "all within spec" - highest was 1.2, lowest -0.8. Again told "normal".... rattle/tapping noise is not "loud"... and no louder when cold.... but can be "just" heard over wind noise with all windows up at 100 km/h towing van. Seems more apparent at a scan gauge l/100 km readout of between 12 & 17 l/100.... seems to be quieter under heavier load.... no noise coasting (ruling out mechanical constant noise). Watching this thread with interest.... frats, Rosco