idle drops to 400rpm and eventually stalls

[cjcasati at hotmail.com]

Hi all,

my 86 5KTQ held up fine on the trip to DC to pick up a friend who was stuck
in Newfoundland since Tuesday. But it developed a weird symptom just before
the trip:

- Pulling up to a light after driving some time the idle drops to 400 rpm
(normally idles at 900) and the engine eventually stalls.
- while this low idling occurs (before the engine stalls) I can cut off the
ignition and restart (no hesitation) and it idles normally.
- I can also adjust the idle by stepping on the gas pedal
- car performs absolutely normal otherwise
- Idle problem is intermitent, may not appear for a while
- problem sometimes appears immediately after hard acceleration

The archives hint at a problem with the CIS or the ISV. I had to clean the
ISV a while back because it was idling high with a pulsating jump between
two rpm speeds.

Vacuums appear fine on the engine, car has 167K.

Thank you to everyone as always!
Best,
Christoph

Christoph Casati
Casati Interactive LLC
www.casatidesign.com