What's the serial number on the cart?
There should be a sticker on the right kick panel with the serial number.
IF that's gone, there is another sticker on the frame crossmember below the floor. With the pedal access cover of, look back at the crossmember just above the brake cables.
There were some resistors on the throttle wires built into the harness on certain Precedents that would not allow the MCOR to work with that controller. It's possible the installer just ran new wires rather than track down and remove the resistors. (assuming it had them)
Another possibility is the wiring was determined to be damaged or faulty somewhere between the MCOR and controller.
If you're having problem with jumpy throttle, it's probably a failed MCOR. That should be a second gen pedal assembly which you can update to the new design MCOR 4 with the conversion kit.
https://www.revolutiongolfcars.com/p...conversion-kit