94 runs rough cold - please help!

[removalmachine]

Hi,

94 5.7 TBI.

Runs really, really well, except during cold start. Will start OK, idle will go right to 1100 (or so) RPM, but start to run rough after about 10 seconds. It gets progressively worse, to a point that if you rev it, when it comes down it almost stalls before catching itself. Doesn't hesititate, and once in gear and you're moving it seems fine. After a maybe 5 minutes, it's just fine.

I've replaced all tune-up parts, PCV, no codes.

Could it be Coolent temp sensor, or IAC, or EGR?

It's driving me nuts. Any help would be appreciated.

Thanks

Scott