98LS1driver

iTrader: (2)

My car just recently started hanging up at idle if I'm driving for 10-15 mins on highway and let off throttle the car feels as if it was on cruise control.. Even when I come to a complete stop the idles stay at 1500 for about 6-7 secs then drop to 300-500 then back to 800 what should I start looking at I've replaced the iacv and no change when I look at data stream on me scan tool when I'm off throttle and it does it the scan tool shows .4% throttle is being applied and absolute mani pressure is 91kpa