Perhaps the "Powertrain Control Module" (PCM, what is sometimes called the ECM) has an internal bad connection and/or short causing the fuse to blow. Seems like if this was the case tho' a code for a bad PCM would come up. At least one would hope.
So to some extent I want to suggest replacement of the PCM.
The other possibility, as you know (ugh) is that there is a short in one or more wires going to or coming from the PCM.
I would start with the main power wire that the fuse itself is connect inline with going to the PCM. And bad wires going to the heated O2 sensors.
Then, if that isn't the problem divide and conquer my friend.
With a good wire diagram, disconnet the battery negative cable, and disconnect the pin connector at the PCM, and use an Ohm meter to check for CORRECT continuity at the pin connector to the corresponding female plug in sensor or output componet.
If a casing on a wire has rubbed off, and exposed bare wire to ground you may also read an infinite Ohm reading from that wire to the body of the car.
In the end a visual inspection of all wires may be needed.