m,
Thanks for your response. Gives me an opportunity to budget
for this repair!

Steve,
The idle went up just recently. Not a slow development, but rather from one day to another. I'll take the car in on Monday
and let the mechanic run some tests. Hope I do not need
to replace the valve. Let you know anyhow.

__________________
1989 300CE (aka Schatzi)
2002 Ford Explorer