Use oem parts here.
I tried a tvh sensor once, the optical eyes are set too high and too close together. Truck acting as you describe. Raymond sensor - all good.

You can probe the connector with a voltmeter. Pin 3 is +12 supply and 1 and 2 are sensor feedback, grab b- wherever. Take the disc off and put metal over the eye to close the switch and you can see if it's opening and closing. Typically open has 0-3 volts and closed 10-12. You may have a dead eye.
Good luck.