@Smarticus The Thrustmaster TCA Throttle Quadrant uses the same control assignments for its fuel levers as we do in the Vulcan (as well as our other products like the 146 and Hawk). The fuel levers on the quadrant are two-position switches, which hold either position (either fuel on, or fuel off), so whatever position the fuel lever is in on the throttle quadrant, it will continue to force the fuel lever in the simulator to the same position.
If the fuel levers on the TCA throttle quadrant are in the "fuel on" position, this will force the fuel levers in the simulator to also be in the "fuel on" position, which for the Vulcan is when the throttles are in the idle thrust position. Advancing the throttles will then fight against the fuel valve control assignment which is trying to keep the throttles at idle and can lead to the throttles "snapping" back to idle whenever the throttles are not being moved.
As a way to guarantee that these switches do not affect the Vulcan (or any other aircraft with combined throttles and fuel valves), we would recommend creating a new controller preset with the conflicting control assignments removed. To do this:
Go to MSFS Options > Controls Options
At the top of the page, click on the tab with the name of your throttle quadrant
At the bottom of the page, go to Open Preset Manager > Duplicate.
Enter a name for the new controller preset (for example "Vulcan"),
With the new controller preset selected, use the "Search By Name" field on the left side of the page to search for and delete the following control assignments:
TOGGLE ENGINE 1 FUEL VALVE
TOGGLE ENGINE 2 FUEL VALVE
SET ENGINE 1 FUEL VALVE
SET ENGINE 2 FUEL VALVE
SET STARTER 1
SET STARTER 2
With those assignments deleted on the new controller preset, you should no longer have any controller conflicts with the throttles in the Vulcan or any other aircraft that uses combined throttles and fuel valves.
I hope that helps.
Mark - Just Flight