WTF is up with my sr?

[Nismo240SX]

aight, i've already had a thread about my sr with a white gunk i believe that is moisture build-up. okay when i start my sr up, it runs and idles perfect... no knocking at all. i walked out of the garage, left the car on, thinking it might rid my moisture problem. well after about 5-10 mins of running time i hear the idle dropping. as i go to see what the problem is, its revving itself up to about 2k and dropping to about 1.5k. and its knocking, so freaking loud its like i'm grinding my teath. and again appears this white gunk in my oil cap. so i shine a light through my valvecover and peek in, and find out this white gunk is everywhere! what the hell! its all in my head. but theres no coolant in my oil vice versa, and theres no smoke coming outa my exhaust. all i can come to conclusion is the white gunk is settling in my oil pan when its cold, i start it up, the gunk risses and spreads, and blocks oil to my lifters or something in my head to make it knock like the tinman is getting it on with dorthy! what the hell? anybody know what the hell is going on?