Its a tune issue... you need too add a good amount of timing to ease starting of cammed stock compression cars. I typically will add 5-10 degrees below 700 RPM and I target 800-900RPM idle. This really helps with stalling issues and also helps starting. One of the tricks of the trade dealing with cars that die returning to idle coming to a stop is to add spark BELOW where the target idle speed is... so say we target 800RPM idle.. Then at 750RPM I will add 5 degrees and at 500RPM I will add 10-15 degrees. So when the idle does drop suddenly its not all up to the IAC to add air and catch the falling RPMS before it dies. When spark rolls in the engine will automatically get more efficient, fire harder and idle higher then when the RPMS go back up the timing comes back out and the IAC takes over... sort beautiful 50 yard pass where the running back is running like hell and the ball magically lands right in his hands and score a touchdown.... something like that haha.
1999 GT 630rwhp on pump, TFS Heads, MMR 4.75L, Highly Modified Kenne Bell 2.1 @ 20lbs, Custom Intercooler, JLT High Boost CAI, CMS Custom TFS Specific Cams, 3.55s, MGW, T56