Yup, head temp sensor is a multimeter reading.
I dunno Rick, I'll take your bet.
I don't think fuel pressure regulator fits the symptoms. It's pretty rare they would go wrong, and if so, it would be constant instead of good when cold/bad when warm.
Djet high idle:
1. Throttle butterfly not closing squarely.
2. Overly advanced timing.
3. Vacuum leak below throttle's butterfly.
There are a lot of potential sources for vacuum leaks... Tracing can be a pain, but it most certainly can be a simple and methodical process because there are only so many potential sources between the butterfly and the heads, so follow the path....
-Injector seals (2 per injector)
-Phenolic block between heads and intake runners
-Rubber boots between intake runners and plenum
-Crack in plenum (usually around vertical reinforcement tubes)
-Gasket between plenum and throttle body
-Excess wear around butterfly pivots
-Air bypass / idle adjust screw in throttle body
-Any vacuum tap on plenum or throttle body below butterfly. (Some of those taps have to be traced upstream to parts that can cause the problem, like the AAR. But on Djet, you can just pull the hose and plug the hole to help troubleshoot most of those.)