99 venture head gasket???

Hello folks

I have a 99 venture with 200,000 km on it. Recently it has started to overheat and lose coolant (no external leaks). There is also an occasional misfire code PO302. I pulled the plug on cylinder 2 and it looks fine. There is no coolant in the engine oil, and the rad pressure test came back fine (it held 15 psi for several minutes).

Could it be a bad head gasket and still hold pressure? The car drives fine other than a slight miss, probably ignition related. No puddles or white smoke..

thanks for any advice

does the temp gauge fluctuate up and down? or does it just keep getting hotter?look under the oil cap for a white mayonaisse and on oil dipstick. how long since you replaced the thermastat?