I recently purchased a 1994 Audi 90 CS with 181000 miles (probably my first mistake).
Anyway, it failed the emission test in Ohio with very high NOx readings. CO and HC were in very acceptable ranges. I was told it is probably the catalytic converter. Well unfortunately, I think the car has two cat converters and they run around $300 each.
Does anyone have any experience with the universal catalytic converters (which run about $90 each) and getting them installed in a
90 CS? Any problems with these and integrating into the exhaust system?Does anyone have any other thoughts besides replacing the cat conv to reduce NOx emissions? I already changed oil, changed plugs, changed anti-freeze and air filter. None of this helped NOx, reduced CO and HC a bit, but NOx actually went up.