The '04 Cayenne S is down. I have misfires - cylinder 1,3,5,6,7,8. I also have a code for P0102 (Mass or Volume Air Flow A Circuit Low); P0130 (02 Senor Circuit Bank 1 Senor 1); and P0300 (Random Misfire). Car runs rough and low idle. I took it to a shop and the info I was given is cylinder 8 has low compression. Got it back and left it running in the driveway for a few minutes. A puddle of coolant appeared - passenger side. I also get a whooshing type noise right near the center of the engine coming from intake manifold. I've changed plugs, coils, battery, and AOS diaphragm since the issue. Oddly, I also developed a hissing noise coming from the VVT solenoid on the driver side (possibly the gasket failing on the intake valve cover - the hissing is not coming from the AOS diaphram).

Head gasket? Is the cylinder making a vacuum and creating the whooshing? Or is there something else amiss?