high ideal is caused by two factors.
- The carb is being opened by its driven arm mechanically.
- You have a vacuum leak somewhere in the intake manifold and it is drawing in air, A lot of air!
I don't know what your carb is but I can only assume it could be at best a throttle body fuel injected.
Some carbs have a ideal salenoid that will force the venturi shutter at the base of the car to close tighter, this helps to prevent cars to keep running due to low octain fuel when turned off.
In many cases, the molded ajoining plug that comes out in one wire may have a jack hole to accept a single wire plug.
Also, look on the pluig for a mounting screw hole that could have a conductive surface on one side, if so that plug needs to bolt onto a ground locally.. the car should have ground wires already attached to the carb, you need to make sure of that because the gasket between the carb and manifold will not allow ground.
So if you do have a ideal solenaoid, look there to see if there is an a spade waiting for a connection.. etc Get an electrical manual for the car.
also