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.
Quality and not quantity counts.
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Last edited by ron1004; 04-24-2011 at 12:16 PM.