Has there been any progress made on this?
My 22re had the same problem because the wire to the knock sensor had been cut through from wear and tear. When the computer doesn't receive a signal that there is no problem with pre-ignition it decreases the power to fight any knock. I guess they thought, better safe than sorry.
Anyway, all I did was to resolder the wire to the pigtail connector and the problem disappeared. Might be worth a look if you still have the truck