hydrogen or hho gas
have you the room to put a spark plug extender in the upstream o2 sensor hole with the 02 sensor screwed into the sparkplug extender? hho or browns gas tends to leave too much o2 in the exhaust, the o2 sensor sees the 02 count and adds fuel. moving the sensor out of the direct flow MAY or maynot help you. i have read where folks had good results, others, no change.......ya may want to spend some time perusing the net for browns gas, alt fuel, hho. there is a buttload of info out there in cyberspace and folks that have been down the same road you are on..best of luck bro.