Jeep Repair: 02 jeep grand cherokee high reving, jeep grand cherokee, grand cherokee

Question
My 02 jgc has recently started reving up to 2,000rpm when being started in am after sitting overnite.  it takes several min to get back down to its regular idle of 600rpm.  I recently replaced the battery.  one mechanic said it might be the idle control valve and another said the battery that was replaced had something to do with it and would reset.  That was 2 weeks ago and no reset as of today.  Your thoughts?

Answer
well the thought of the battery resetting the system only works if you leave the battery off for at least 12 hours, totally unconneted. I would try that first and then i would look at idle control valve or sensor. Try the battery frist. Hope this helps