Texx is 100% right (as he usally is 100% of the time), dont matter what way its connected. This sensor connected wrong or not connected wont give you a high idle but, it would throw up the check engine light and a fault code. I dont know what the original engine set up was for the Sera, if it had an inlet mani similar looking to the 4EFTE one with the idle control valve at the drivers end of the inlet manifold, if so then the problem could be the TPS or the idle control valve stuck open. If it didnt have the idle control valve at the end then the idle control was built into the throttle body of the Sera then some wiring changes will be needed.
If you had a pic of the original Sera engine fitted it would be a great help here.