The engine computer is programmed to increase the idling speed during cold start till it receives signals from the various sensors that it is ok to reduce the idling speed. When the idle air passage air flow has any restriction due to accumulation of dirt, it would affect the idling, which in your case was improper idling at cold start.
Cleaning of the throttle body has restored the air flow and the difference is what we should be expecting, meaning you have resolved the problem.
That is the reason we suggested cleaning the throttle body and a good thing is you asked after performing the job. It is much easier for us to explain rather than you asking when you don't understand or know what could happen.
Sunday, September 30th, 2012 AT 7:26 AM