Loud pop, now high idle

I just turned my key on and heard a loud pop from under the hood. The car didn't want to start at first and took about 6 or 7 rolls more than normal to fire, then it was idling at 1300-1400 rpm instead of the normal 900-1000. I was able to move it into the garage without touching the throttle.

I just got home from a short cruise and shut the car off while I moved my bike out of the garage. This happened when I went to start it back up a few minutes later.

I had just changed the IAC response time from 303ms to 250ms in the computer. That's the only thing I changed other than the tip in/throttle accel pump settings. Did I blow up the IAC??? TPS is working like normal, and the MAP sensor looked right so I don't think it's a vacuum leak...

AEM computer so no codes. No MAF either. The car wasn't even running when it happened. My first thought was a vacuum line popped off but they were all still on there. The car was still pulling 17in hg vacuum idling at 1400 so I figured it's not a vacuum leak...

If I can find my old IAC I'll try it tonight and see what happens.

Well now I'm thoroughly confused. Swapped IAC's, same problem. Unplugged the IAC, idles fine at 850-900. I did have the IAC set at 50% for an idle of 950ish, but now I have to set it down to about 15% for it to idle below 1000..... And with it set that way, after fixing my timing which somehow was a couple degrees advanced, it idles perfectly at 950 with no surging or hunting which is new... Any ideas?


Oh yeah, I checked all 3 of my vac lines and they're fine. Vac at idle is the same as it's always been, which is bouncing between 10 and 12in hg at 950 rpm.