Don't you have a programmable computer? Can you program out open loop? If I understand correctly, the only reason WOT closed loop requires a wideband O2 is if it's expected to make maximum power, and you could just program it out and lose a couple HP at top end...

If the TPS is the only way the ECU knows you're at full throttle, then hacking that with a resistor in the right place might work... unless the ECU figures it out and faults it.

HHO (more commonly known as H2O, or water) is very stable, already oxidized. HHO will not oxidize hydrocarbons. If you are referring to H2, H2 cannot oxidize anything, it is a powerful reducing agent......not an oxidizing agent. Basic chemistry. High School stuff.

If you know so much about basic chemistry, you should know that HHO is NOT the same thing as H2O. HHO is Brown's Gas. It has very different properties than water (despite having the same base elements in the same ratio).

You can run a welding torch on Brown's Gas. Can you run a welding torch on water vapor or steam?

The Canadian Hydrogen Energy Company guarantees a minimum of 10-percent improvement for diesel trucks using their hydrogen fuel injection technology, (which is really HHO gas). Results are likely more since this is a minimum.