Extreme surging/stalling

Do a search and you'll find a 100 posts on this. Basicaly you have 2 choices, you can install you're stock air box(silencer removed and K&N), or you can fool around with the sampling tube position( by clocking the meter). I installed 30s and a 76mm c&l among many other things, with a cone on the c&l and sampling tube turned to 3 o'clock(looking at it from front of car) it would idle and drive great but it would not cold start. It would fire right up and as it came off of high idle it would stall till it got warmed up. I don't have the patience for such drivability problems so I reinstalled the airbox and put the sampling tube back to 12 o'clock and she fires right up. This summer I will get a Moroso cold air kit and fiddle with it, I know lots of c&l users have had good luck with this kit, and the meter clocked to 3 o'clock. It probably won't be worth any power over the stock box with a K&N but I hate the way the stock box looks. I just noticed you unpluged the IAC and the idle didn't drop. That is usually an indication of a vacuum leak, which will also cause an eratic idle. Double check that you don't have a vac. hose off or an intake leak somewhere. Good Luck.

did you have the mass air flow meter programmed for the new setup?

first off check for ANY vacum leaks.... I went your route with all the sensors, and ran my codes about a thousand times and never got a single one relating to the maf, egr, act, ect etc... When i was replacing the gasket that goes from the lower to upper, i figured that i would test the egr valve. You just simply pull the vacum line off, and blow on the little nipple to make sure its not leaking any air out... Well the diaghram in mine was shot, and i had two vacum leaks the size of nickels from it.... Just my .02....

i think your MAF sensor needs to be calibrated for 30lb injectors or else the computer will think the engine is stupid

Full tune-up and check your fuel pressure. I had a similar issue that you described and the tune-up and adjustable fuel pressure regulator resolved it. I also cleaned all my sensors and electrical connections. Sometimes I can hear that the car 'wants' to surge, but it doesn't. The stalling was making my car undriveable, too. It was also embarrassing when the mad surge began at idle.