Sport Quattro problem

[ccohen5]

| When I first registered this car on the East Coast it passed emissions
| easily with a HC level of nearly 0.
|
| Today its another story with levels near 500 parts per million, two years
| later.
|
| AFAIK there is only one adjustment that can be made and that's the screw
on
| the MAF.
|
| During the 2 years maintenance has included a new timing belt, water pump
| etc, plugs and all filters including both fuel filters and a new O2 sensor
| (there is only one).
|
| I am being told that the cat is cooked because the temp differential at 3K
| rpm is only 50 deg F and should be closer to 100 deg.  The idle is rough
and
| has been getting rougher over the 2 year period.  It still pulls about 1.7
| bar boost and has no hesitation revving to 6K and I have taken it to red
| line at 7K on one occasion.
|
| So my question to ye Audi brethren of the 20V fraternity is as follows:
|
| Should I replace the cat?  Its a custom fit by Bauer in Germany when they
| did the A/C for these cars and the car was fully federalized.  But I know
Ur
| S4/6 that pass emissions without cats, so should I bother?
|
| What could have caused the progressive enrichment of the mixture, or where
| should I look for the fault?  Both shops who have had a look are
scratching
| their heads and talking about faulty injectors, too high fuel pressure and
| failing MAF?
|
| What say you?
|
| Many thanks for any suggestions.
|
| Oh BTW - they tell me that it is better to have a cat operating as that
will
| improve the chances of getting the emissions into the range required.  And
| even if I cannot entirely fix the mixture issue once I spend the $460 (or
| more) on the cat, I will have done enough to get a 2 year waiver in VA.
But
| I would like a leaner mixture without running the risk of blowing a
piston.
|
| Colin
|