The path extrude tool can produce strange UV coordinates. You may find that the lathe tool works better for objects that need to be UV mapped.
If you have to use the path extrude tool, make sure the extrusion path is drawn as uniformly as possible.
You can also correct the UVs on a path extrude object by converting it to a Bezier surface, and then taking the object into an edit session. Now you may want to reduce the complexity level, and convert the object to a polygon mesh.
These steps can help correct the UVs in path extrude objects.