One guy rotated the sensor as other guy "drove on the dyno". They both were checking the input signal and when it became visibly smoother in the scope; they tightened it up right there. I haven't had to touch it since... I avoid touching it now when working around it because the whole process was such a pain.
I bought and went through 6 tps sensors before the dyno appointment. That was a rather expensive day, but the car's run great ever since.
"I'm gonna sing the doom song..."