Accelerating at idle

1998 3.0, v6. Manual Trans, A/C, approx 190thousand miles. When coming to a stop the engine actually increases RPM’s and runs at this increased RPM until I shut the engine off. When I restart engine still racing. It does this intermittentaly approx 50% of the time doesn’t matter if A/C is on/off. Have replaced O2 sensor, idle air control valve, EGR solenoid, and valve. Had the last done on 4/23 on 5/1 it was back to idling high. This has been a ongoing problem for about 5 years, replace items works for a short time and then back to the idling high.