93' mustang, 4 cyl. starts ok, then after a minute or 2, it wants to stall, runs rough, backfires occasionally, have to pedal it to stay running. After about a minute of this it goes away and runs fine. The problem only occurs when engine has cooled down. I had it ran for codes and checked out ok, however, it was done while engine was warm.

Any advice is appreciated.

check your coolant tempture switch