well i just did a compresion test and cylinder #2 is only getting 30 to 50 psi.... its not the rings, cause i tried oil in the cylinder, so its down to valves or head gasket....the head gasket was replaced recently but i dont know how good of a job was down, the oil is mirky looking but i dont know if it is coolant or exhaust... is there a way i can tell, any help would be greatly appreciated

89 4Runner, 5-speed, Rebuilt 22RE EFI, DOA C270 cam, Pacesetter Headers, 35x12.50x15 MT/R, 4" Superlift Susp, 3" Body Lift.