Warm Engine Idle Issue

Maybe a long shot, but makes sense to me. What if the voltage regulator which is mounted on the firewall in close proximity to the headers is getting too hot and reducing the voltage output. Below is the chart from the manual showing how it decreases voltage with an increase in ambient temp. I'm pretty sure it's well over 140F. Thinking about getting the engine to duplicate the gripe and then shutting it down quickly and piggy backing another regulator in and firing it back up to see if it fixes it. The AC and lights work fine until it gets hot and the engine starts to do it's thing.
regulator.jpg