67 twin turbo dart

Not sure what you mean by trimming the sensor .
First i would unplug both the sensors then put a wire loop into the 2 sensor holes shorting 5v to ground to prove the gauges both go to max.
Then measure to sensor resistance doesn't matter hot or cold to prove the sensors are good
Then plug in the sensors and measure the resistance across the 5v & ground wires to see if it matches the measured value