Hairy green toads from Mars made email@example.com say:
> Hello all,
> One of my '86 5kcstq's has started ilding at about 2500 rpm. This problem is
> intermittent and there doesn't seem to be any particular thing that makes it
> happen (or quit happening). When it starts idling at a normal speed, the rpms
> drop suddenly, just as if I had just taken my foot off the gas pedal. I have
> checked the throttle linkage. No problem there. Could it be the throttle
> position switch? I can hear it click when the throttle is moved to the idle
> position. Is the throttle position switch supposed to detect WOT? It does
> not click when the throttle is wide open.
I had this problem last year on my '89 100Q. It was the devil to track
down. Tried cleaning then replacing the idle stabilizer valve. Nope.
Checked all the vacuum lines for leak. Nope. Even thought about replacing
the throttle body. Nope.
It turned out to be the dashpot spring/plunger inside the throttle body.
It had corroded just a bit, and was a little sticky. It would occasionally
stick open, holding the throttle body plate open a bit. We just yanked the
spring/punger out (can't get it separately; need a throttle body $$$$).
The car works fine now.
Andrew L. Duane (JOT-7) firstname.lastname@example.org
Digital Equipment Corporation (603)-881-1294
110 Spit Brook Road http://www.zk3.dec.com/~duane
Nashua, NH 03062-2698
Only my cat shares my opinions, and she's too heavy to care.