[Luce]

Before you go too far into changing things, read up on adjusting the VR pots. One is for hysteresis and one I think is sensitivity. If it's getting extra signals, you may need to tweek up the hysteresis. They also have a few suggestions on pull up or down resistors and such to tame noises. You may also consider changing the jumpers to bypass the VR circuits altogether.

The VR is an AC signal and the hall should be 0 or some voltage. I think the VR circuit is seeing a very slight dip to neg output on the hall and makes it trigger when it fluctuates between -.01 volts and .01 volts.

If I was in your shoes, and decided it was time to try something different, the first thing I change would be the jumpers in the ECU to bypass the VR circuit. At least your not opening up the harness.

Hope this helps