i have a 1990 chevy lumina euro 3.1 i recently replaced the tps because it ran rough on idle and would stall out if i reversed too fast or rev'd the engine to high in park. After replacing the sensor while in park the car idles high and when put into reverse or drive stalls out sometimes. Was wondering if there is any way to turn down the idle

 

Have you tested you idle air control valve?

Have you checked for vacuum leaks?