5TQ Stalling

[Doyt W. Echelberger]

When my 87 5ktq began stalling at toll booths, after coming in off the
turnpike, I puzzled about it for months and checked every vacuum hose and
electrical connection, especially the electricals in and around the
throttle switch (known to fail early in every case....microfractures of the
internal solder joints.) If you haven't replaced the throttle switch, ever,
it is due.  Also, big vacuum leak is the soft spot on the lower underside
of the crankcase breather hose. And there are others. Michelin Man hose,
ISV....etc. If it idles fine at 760, the ISV might be OK. You can always
disconnect it and drive without it, and see if the stalling continues.

Eventually, I did the dipstick vacuum leak test and the car passed.

But after fixing all the vacuum leaks, and electricals, it ran pretty good
but still stalled. Then the stalling turned into an immense loss of power.
Couldn't keep up with traffic. Towed it to my mechanic, who found the
faulty oxygen sensor with his duty cycle tester. Badly out of specification.

I replaced the oxygen sensor, and the stalling ceased. That was two years
ago. Probably needs another one by now, or will. Guestimate is q 30k miles.

You may have other issues, but that's my stalling story.

Doyt Echelberger
Ohio   USA
 >>>>>>>>>>>>>>>>>>>>>>>>>>>>
At 11:59 AM 6/26/2003 -0600, you wrote:
>This is a multi-part message in MIME format.
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>[ Picked text/plain from multipart/alternative ]
>One of my 5TQ's is stalling when decelerating to a stop.  The car starts
>again just fine.
>
>I have checked the decel valve and tried running the car with the decel
>valve disconnected (electrically).  It still stalls.  Idle speed is 750 rpm.
>
>Does anyone have any suggestions?
>
>Thanks
>
>Ian
>************************************************
>Dr. Ian McArthur, Consulting by Acronym, Cochrane, Alberta
>sutul at telusplanet.net
>--