[V8] Sputtering Green Horney

[Roger Woodbury]

I am about to buy a trade the Audi in on a Honda Element.  

Well, no.  Not really.  But our 1994 Audi 100CS Avant has an horrific
problem that defies diagnosis and repair.  I am almost, ALMOST mind you,
desperate enough to take it to the Audi dealer for their diagnosis.  My
wrench is so far unable to find the problem, and we have about eliminated
everything possible.  Here's what is happening.

Basically, the car is a 130,000 mile example, and it has had continuous and
significant maintenance throughout its life. The problem that it is having
is ignition related, it seems pretty clear.  This started last year, with an
on again, off again sputtering that seemed for all the world like bad wires,
OR bad gas.  We use ONLY medium grade premium with an occasional dose of
super high test, and we buy fuel from the same two stations all the time,
unless we are traveling a long way out of the area.  

Last summer I replaced all plugs and wires and the problem seemed to go
away.  Occasionally we would get a mysterious "check engine" light and a
trip to the wrench's computer did not yield what I expected, which would
have been an oxygen sensor.  We have had one o2 sensor replaced about 60K
ago, and I suspect that is what the issue is, regardless of what some
computer is saying.

Throughout the fall and into the winter, the car has been running oddly.
The car always starts fine, and idles with no difficulty.  But under load
the engine seems to be breaking down...much like one or two or three
cylinders are misfiring randomly.  Then the check engine light will come on,
and sometimes, the engine will smooth out and run normally.

After an hour or so, having reached our destination, the car will start
right up and run normally.  Then ten miles or so down the road, the "check
engine" light will come on again, regardless of what the engine feels like
or is doing.

The next day, the car may run fine and feel normal.  We are traveling to my
parent's home regularly, and it is nearly 50 miles each way.  Sometimes the
car bucks and snorts....feels rough like misfiring...and sometimes it
doesn't.

We have done another complete tuneup, and replaced the coil this time, which
was original and which the wrench was probably the culprit.

Nope. Not close.  Today was about the worst that I have felt it.  I just
drove to the post office and back....about ten miles round trip...and the
sputtering was noticeable in steady driving. 

I wonder if the distributor itself might be failing.  Upon acceleration the
car doesn't want to accelerate, and where it should drop down a gear, it
doesn't unless heavy throttle is applied to MAKE it downshift.  Has anyone
had distributor failure on one of these cars?

I also wonder if this might be some sort of computer failure, since it is
random, perhaps it is a corrosion problem, although it doesn’t' seem to be
getting worse...it just IS.

I am doing a mileage test right now, and will check the mileage tomorrow.
The car will have had three trips to my parents' this week, and the miles
will have a good mix of normal around town (semi-rural), and over the road
distance travel.  I am expecting around 22 miles per gallon, which would be
normal for this car.  If it is significantly less, then I will direct a
change in the o2 sensor.

We have done a lot of work on the car to keep it in service for another
100,000 miles or more, so this is really vexing.

Any ideas? 

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