I see this in electrical issues at work all the time. It is usually caused by intermittent contact of the terminals somewhere. What happens is that the terminals aren't quite touching (small gap like 0.01 mm), so the voltage arcs across them. Eventually, the arcing will corrode the terminal, but until then it could show the bouncing that you are seeing. You can see the arcing by looking at the male pin - it looks like it has a little burn spot on it.

In terms of temperature, as terminals get hotter, the conductivity of goes down. So it may not have been noticeable when cold, but it gets worse when hot. It is not necessarily under the hood either. Yhe arcing creates its own heat and could be anywhere between the engine, PCM, dash wiring, and even in the cluster.

That is my guess though.

-Geoff

 

Good to know. I didn't think of it this way. Thanks guys.