At 135k at the very least the upper plenum did not look like this. It was jus a bit bronze looking but not black gunk. At 135k I had it opened up cleaned following items egr port, egr valve, throttle body. Replaced pcv valve then also with aftermarket valve. At around 150k changed pcv valve with oem valve. Soon after decided to change leaking front valve cover gasket and this is what I was greeted with.