--snip--

Of course it would be helpful for someone else to do a long drop (20 to 30
minutes) in cool temps using the engine for braking, i.e., foot off gas
for like, 95%, of the time. 2nd gear on AT, for me, and report back on
what their temp gauge says. Such a person would of course need to live
someplace mountainous, and have nothing better to do.

--snip--

I just did this on my drive back from Mammoth, mostly engine braking down
the Sherman grade. I too had the temps drop way down, into the white as I
recall, but no other symptoms. However I started getting the low power,
cough-cough bit while in Laughlin last week- just as my temp II sensor went
out. I don't even know if there is one on a 1.9, but what you described
sounded much like what just happened to me.

Cya,
Robert