= rev4 1996 GTSPreviously i'd been having some problems with my car, smoke was coming from my BOV when in use.
On the way home the other night the engine warning light came on, the subsequent error code was 52 - knock sensor. On Saturday i did a compression test, the results: all cylinders were 164psi except cylinder 4 which was at 70psi (the cylinder on the air filter side NOT the intercooler side if that makes sense).I removed the oil cap
(see photo), it has some slimy gunk around it inside it. I removed the pipe to the catch can, inside here was also some gunk (see photo). The spark plug to cylinder 4 was a lot blacker then the other three.So here's my question.
Is there anything more I can do to diagnose exactly what my problem is or is this enough information. The compression test kit suggests: insufficient valve clearances, worn piston rings or cylinder bores, poor valve seating or burnt valves, leaking head gasket. 
