Welcome to the forum broer.
I would pressure the service center on the coincidence of this fault appearing at this time.
The Idle Speed Control valve (ISC) controls the idle speed under varying load conditions - is typically mounted on the throttle body and bypasses air around the closed throttle plate for the idle needs. Sudden malfunction is possibly a bad connection on this, or an inlet manifold vacuum leak.
The service center could have left off a vacuum pipe, or not connected the ISC securely.
If the onset of idling problems are gradual, and not at the time of service work, then it's often caused by a fouled up ISC, which can be cleaned using carb cleaner.
I would insist on watching what is done to correct the problem.
Note: The ISC is often also referred to as the Idle Air Control valve (IAC)
Take a look at the KiaTech web site for more tech info.
For service info register (free) with KiaTechInfo and click on 'Shop' on the left, and for elect schematics click on 'ETM'.
Quality and not quantity counts.
Sig image is 500X100 at 11.7 kb
Last edited by ron1004; 04-24-2011 at 12:16 PM.