Originally Posted by Ron_L
It's possible that you were chasing the temperature by changing the vents too often, too. Make small changes and give them time to take effect before making another change.
+1. Make small changes in the intakes. Wait for the temp to settle in and then adjust again if necessary. Sometimes mine will settle out then drop a few degrees and then go right back to the temp I wanted. Not sure why, but that's what it wants to do. Once it drops and comes back up it will usually hang right there for hours on end with only 3-5 degree variances. Can't ask for much better than that.