Test your ECT, engine coolent temp sensor. It controls 3 things for a cold start; the EGR, ignition timing and fuel mixture. This is the first place I would look.

Im not sure what the IAC is. Intake air control? Is this the air intake temperature sensor mounted in the intake manifold? If so, it helps compute air volume for fuel mixture, but does not affect the EGR operation and timing during cold engine operation.

It you remove it, they recommend to replace it instead of reinstalling it because it can crack the ceramic and you may not know it.

Mark