Re: Poor Idle when hot

[Chris Newbold <cnewbold@transarc.com>]

At 10:05 AM 6/22/98 , Todd Young wrote:

>1993 90S with V6 engine. when hot the engine
>will die unexpectedly. Noticed it seems to happen
>when digital ambient temp readout goes over 100.

Does the idle also hunt up and down a bit? Not necessarily rough,
just unstable?

That's how the ISV died on my 1993 90. Fine when cold, but once
the engine was warm, it couldn't hold an idle. It was worst
right after highway blasts.

You could try cleaning it, but I understand Audi had a defective
batch of these things; mine was replaced under warrantee...

>often. Also experiencing poor mileage and rough idle,
>as am I. Only getting 22-24mpg around town,
>understand this is low for this vehicle.

22-24 in town on the V6 90?!?! Do you get out and push? :-)

I've never broken 20 around town and usually get 25-27
highway depending on how hard I push it. Right now in heavy
city traffic I'm getting around 16 MPG. (And this is with the 5spd.)

If you've got a rough idle and (truly) poor mileage, one or both
of your O2 sensors may be on their way out. I don't think I've ever
heard of a bad O2 sensor resulting in stall-outs, though. It doesn't
have enough control range to mess up the mixture that much (and even if
it did go completely out of whack, the ECU would have recognized that
and switched back into open-loop mode and turned on the "check engine"
light).

-Chris
1993 90CS