Look through the posts on this group, one will find that cleaning the Idle
Speed control valve will usually verify that the problem resides there.
However, the result is often temporary.. or the indications change without
fully fixing the problem.
This may be a result of the motor itself being bad or sticky - cant be
easily accessed to clean.
The fix, once it's been determined that cleaning affects it, is a new one.
Preferably from the OEM.