bouncing Idle?

When I come to a stop light and I’m idling the idle bounces and I’m hoping its not major 1990 automatic LS 4dr any suggestions

how bad is the bouncing??? what range of RPM is it going from?

like 750 up to 1100 I’d say

need to know more dood… is it when it’s on park? or drive? is it when the temp gauge is cold or warm? tell me as much as you can.