2000 explorer rough idel at start up

I have had this problem before. I replace the IAC unit and it solved my ploblem then. This time I replaced the IAC unit and it still dies when it is first started. I can keep it running at about 2000 rpms but it wants to fluctuate even with a stead feed of fuel. It runs fine after about two minutes or after I take it for a quick drive around the block. After it warms up and for the rest of the day it starts just fine. I need help, any ideas or suggestions would be appreciated?

Which engine does your Explorer have (V8, V6 OHV, V6 SOHC)? Have you checked for vacuum leaks, including the PCV elbow and the intake manifold, which are pretty common issues on the V6? When's the last time a tune up was performed, including fuel filter?

-Rod