You might try placing a vacuum check valve between the intake manifold and the control valve. When the intake vacuum drops do to heavy right foot
, the check valve will prevent air from relieving the vacuum in the line. When the vacuum returns (off the throttle
), then the line will continue to be evacuated by manifold vacuum. The check valve is less than 2 bucks at any parts store. If you add a canister for "vacuum storage" then you need to have a check valve between the canister and the manifold. You may also have a leak, but this should keep the heater from going on and off.