Temp Sensor Relocation

[FiveOoutlaw]

I just deleted the heater core and heater lines on the manifold. I capped the water pump and then moved the sensor to the lower manifold. The reducer that I picked up (3/8 to 1/2) doesn't thread all the way in nor does the sensor into it. Since then the car won't idle or run right, I'm guessing because its not getting a good reading on my speed density system. Is there anyway to get these to sink farther in to get a proper reading?