What is the problem with my suspension fork?
Your fork has both air and oil in it; if the air component is fine it follows that the oil component is not.

If it was not stored upright the problem is probably that the oil is in the wrong part of the fork and will gradually make its way beck to its designed location if you leave it the right way up for a day or two.

Check for oil leaks at all points around the fork (and oily residue wherever you had stored it).

The other possibilities are:


an internal seal has failed and is no longer controlling the flow of oil/air within the fork leg as it should be;
the oil has become contaminated with water;
the oil has broken down into a foam.


In any of these cases it will need to be disassembled and serviced: I would leave that to the professionals.