Surging Upon Start Up

I have a 1995 Chevrolet Suburban with a 5.7 Liter enigne in it. When you first start this vehicle, either cold or hot it will surge for about a minute and then straighten out and idle fine. It has had the MAP sensor, IAC valve, Distributor, Thermostat, TBI gasket all replaced. This vehicle also had the idle learn done on it several times, but to no relief. Is there anything that I have missed that could be causing this issue? Any help would greatly be appreciated.

sounds like the iac isnt working properly

I had the same problem with a 91 suburban, changed the iac twice & rebuilt the throttle body w/ new fuel pressure regulator, all to no avail, I sold it & the new owner has not fixed it yet.