Idle and surging problems.
Before i switched out my EGR valve, control valve, IAC and PCV valve my car would idle at 1500 for about 5-7 seconds then gradually drop down to about 950 whenever it got to a full stop. Now that i replaced those 4, my car idles at 1100-1200 when i get to a full stop and now it just stays there unless i give it a nice rev and it drops down to 800 and surges up to 950 after 15 seconds. Also my scanner just let me know my bank 2 CAT is bad, would the cat's have something to do with this idling and surging, or is there something else wrong with my car. Any input is much much appreciated.