[s-cars] Emissions Test Failure

[Jim Bonnet]

Kaklikian, Gary wrote:
> My '92 S4 failed  the emissions test, in particular the hydrocarbons at idle were very high. All other readings (CO,CO2) were normal at idle and at 2500rpm. The car has had a stumble off idle recently, so I suspect it may be running rich at idle. I checked the throttle switch per the instructions on S. Mockry's site, looked for vacuum leaks, and pulled the ECU codes, all to no avail.
> Anyone encountered a similar problem?
>
> Thanks,
> Gary

- Ignition system malfunction (plugs, wires, coil)
- Incorrect air/fuel mixture
- Vacuum Leaks (hoses EGR, Intake manifold, carburetor)
- Incorrect ignition timing and/or idle speed
- EGR valve partially stuck open
- Faulty fuel injector Operation
- Internal engine problem (burned valves, poor compression)
- Inoperative or missing catalytic converter
- Air injection system failure