i have a 97 with 316k and still running perfect, but it has oil in the intake from the throttle body to the mass air flow.
its running the best it ever has. i have already replaced the pcv valve, gromett for pcv was good, check the breater line coming from the valve cover to the intake for cracks, its alittle hard but it was sealed good. no vacuum leaks. idles perfect doesn't miss.