Engine got gradually rougher running and finally would not idle and shook violently and shut down with STOP SAFELY NOW. DTCs P0300, P0303, P0304 which are random misfire, cylinder 3 misfire and cylinder 4 misfire. Checking injectors, plugs and coils revealed no issues. However, a compression check showed ~ 150 psi for cylinders 1,2 and 4 but almost nothing for cylinder 3. I assume it is a bad head gasket but am surprised there is no evidence of it in the exhaust or coolant resevoir. Not sure I want to tackle a head gasket at this point. Even the PCV valve replacement due at 100k looks like more than I want to do. Any chance it is something simpler that I haven't thought of? Any one out there changed the head gasket on a 1st gen FEH?