I am having a problem with my Civic idiling eratic then set off the P0505 code. When the car is cold it idles steady around 1100 rpms, but once I hit the accelerator the engine starts the eratic idle then soon after sets the code off. I have noticed that also the engine is at operating temp and I hit the throttle the IAC Valve is still continuing to suck in air, is this normal? I have replaced everything I know that could have been the problem, new IAC valve, ICM, ECU, PCV, Distributor cap & button, Map sensor. I have also check every where around the intake and throttle body for air leaks and found nothing. When the P0505 code is set off the car is very difficult to drive. It sounds like the engine is missing timing at the point, it kicks and bucks till you get past 2500 rpms the the car drives fine.

Please help me figure this one out.