Engine Starting issue

[Mr.Met1966]

Hi, I recently was coming home from a fishing trip, engines were running fine all day, at least I thought. When I entered the speed zone and reduce my speed,the Starboard engine stalled. When I tried starting it ,it would run for a second then stall again. The engine is a 2004 Yamaha 300HPDI 2-stroke. I hooked up the engine to my computer, (YDS) and notice the error code for the TPS. I made sure the voltage was adjusted, to the specs, .51 then adjusted the throttle to a .61. still no difference. I noticed when I unplug the sensor the engine will start and stay running. I also noticed, sometimes between starts it would not turnover, but if I put the shift in forward and back to neutral, it will start, but stall again. Sorry to be so long winded, but wanted to fit in as much info as I could. Any suggestions would be great

Thanks