The equipment connected with this fuse is listed as the Ignition coils, the radio interference capacitor, the PCM relay and the passive Anti-theft System Module.

I think I would replace the PCM relay as it is the only part listed which has moving parts inside. In addition, you can check if the PCM relay is the same part as the Horn relay and use the horn relay in place of the former PCM relay. If your short goes away, then you know the old PCM relay was bad.

If the fuse breaks before you crank the engine, you could disconnect the coils and see if the fuse still breaks.

The radio capacitor, you need a little better diagram to identify this wire and when disconnected, you would know if the fuse breaks or not.

If its the anti-theft, then that is more complicated to solve. Test all the other stuff first.

Please let me know what you find.