Throttle Responding Problem

If your fuel pressure sender is located before the fine fuel filter as Rotax recommends, then the recent higher fuel pressure readings could indicate that the fine filter is getting dirty and needs to be changed.  Not sure if this would be enough to cause the power problems you describe, but it would be a good place to start.

Jeff B is correct, it could be a fuel filter starting to plug up. You should have a bypass check valve that goes around the fuel filter in case it becomes blocked, you're engine can still get fuel (unfiltered). If you run unfiltered fuel for too long, your injectors can become plugged up.

Please provide a schematic of the fuel system in your aircraft so we can compare it with the Rotax recommended fuel system design.