Flashing the computer on a 1999 XLS???

I asked a mechanic friend why my 1999 Explorer ran rough on start-up, and other times when cold. He said this was a computer issue and the dealer (for $75) or a local parts store (for $60) would "flash the computer" and this would clear up the problem. No CEL or codes showing, but it runs really rough on start-up, first thing in the morning. I replaced the plug wires, but this didn't help. 1999 Explorer XLS, pushrod V-6, 4WD, AT.

Anyone else heard of this?

If your rough running includes idle surging up and down and possibly stalling when loading the engine, then I would check the IAC (Idle Air Control) solenoid. These had a habit of sticking closed, restricting the airflow to the engine when the throttle plate is closed. This is aggravated by a cold engine. One thing to try, with the engine running rough, barely press the throttle pedal just enough to crack the throttle plate, if it smooths our, I'd go ahead and replace the IAC which is just below the splash shield on the top of the intake and only involves two bolts and a connector. I hope this post helps you and good luck. Let us know what it is when the vehicle's fixed!