5KTQ High Idle

[Mark and Aviva Woodland]

Greetings folks,
After being wakened from an early hibernation (June to Novenber) I put Max
('87 5KTQ) back on the road today.
3/4 of the way through the 150 mile shake down cruise, the idle jumped to
3000 rpms and stayed there for the duration of the trip. The good news is
that the rest of the trip was all highway, and we made it home without any
further drama.. almost like cruise control.
Unplugging the ISV had no effect, and I could find no visible tears or
intake leaks. On getting home, I removed the ISV which proved to be closed,
and a manual inspection of all available lines proved fruitless.
I followed this with the WD-40 spray test of all known potential leak
points, hoses, lines, gaskets, valves, etc..."idling" at 3000 rpm. No
changes.
I was kinda hoping to take Max to work tomorrow, Any ideas or BTDTs would be
appreciated.
I also seem to have picked up a prodigious oil leak under the front of the
engine. The front main seal was replaced at the last timing belt change 70k
or so ago, and when the belt was replaced again a few weeks ago, the
mechanic said it did not need to be replaced. I'm kinda vexed that they
pulled it apart, replaced the belt, and never mentioned the source of the
leak, or offered to fix it. Are there any other local points that are prone
to leaking, like the oil pump assembly?
Thanks in advance,
all the best,
Mark Woodland
Max '87 5KTQ 280K