If you have to hold the key to the left and jiggle the hatch (or man-handle it) to get it open, the hatch is on its way to failure. The pins-and-latch mechanism is dependent on proper alignment, so when the glass and frame start to separate, the whole thing goes out of alignment at the latch, making it difficult to open.
Acquiring 924S and 944 cars is a disease for which there is no known cure. We find parts cars, neglected cars and even good cars, but it seems that all of them have something that needs to be fixed or improved – thus the symptoms of the disease.
“I will put some of this in it, and it will be fine.” If it is leaking, it will continue to leak. Magic fluids may help in an emergency, but eventually the leak will come back and it will need to be fixed properly. Magic leak-stopping fluids may get you home, but they are not a permanent fix.
If applying the “theory of last touched,” the first place to start is to review whatever I did before – whatever I last touched on the car.
One of the most common 944 sunroof failures occurs in the latches in the roof. The cable engages a nylon gear in each latch, spinning it and driving the latch up and down. When something goes wrong, this $10 gear is the failure point – nylon vs. metal.