The intake gasket, water pump & thermostat were replaced around 50k, nothing wrong with the pump but was there so...plugs are always looking nice. Took throttle body off cleaned mas etc. ,runs great.
You can stick a fiber optic camera down thru the throttle body and see if there is oil inside the intake on the bottom.
My 1500 5.9 runs great but is sucking oil thru the plemun gasket. When the weather warms up then I'll do the aluminum plenum plate modiflication.