V8 with High Emissions

[scott.john.mockry@bangate1.tek.com]

John,

As others have mentioned the idle mixture CO% (2.63%) is way too high on your V8. 
Assuming your catalytic convertors are working with a 60-70% efficiency you have
a feedgas somewhere around 4% CO upstream of the cats. Typically the feedgas before the cats
at idle is 0.6 to 1.2%. Even the 0.85% CO at 2323 RPM is a little high along with the HC of 213. 
At 2500 RPM the CO% is typically "very" low (0.2 to 0.5%) and the HC  should be closer 
to 100PPM or less.  The V8 fuel/ignition system is "supposed" to be an "adaptive" system 
that would compensate for minor leaks etc and if a component  fails it "should" use a default
 value for the defective component/sensor etc. But..........

Here are a few possibilities:
Extremely dirty air filter
Fuel dilution of the engine oil
Evaporative canister purge valve (duty cycle controlled solenoid) stuck open at idle
Coolant sensor open circuit
Fuel pressure too high (regulator vacuum hose pinched off or defective regulator?)
O2 sensor wire grounded (false lean indication) or extreme O2 sensor malfunction
Leaky fuel injector(s)
Hot Wire mass air flow sensor out of whack at idle
Throttle position switch full throttle switch stuck closed (seems unlikely)
(Note: the throttle position sensor (variable resistor) portion of this switch 
is only used for the automatic transmission shift control.)
ECU needs exorcism  by the Audi Gods (well it is possible)

I will try and borrow my friends VAG1552 Scan tool over the weekend and if
you are interested we can check your car for any stored fault codes during the 
Pacific Northwest regional Audi club  get together at Mt. Saint Helens.

See ya soon,
Scott M.