I recieved the following results on my last emissions test, I was wondering if anyone who is familiar with interpreting the results would be able to give me a good idea as to what was causing these results:
Grams/Km
HC - Hydrocarbons 0.4407, below 0.5000 to pass
CO - Carbon Monoxide 1.9679, below 9.3200 to pass
NOx - Oxides of Nitrogen 0.8017, below 1.2400 to pass

My HC was barely a pass, and the NOx readings were somewhat on the high side.
Any idea what this may indicate?
Basically, Would the EGR cause this or would these symptoms be more related to the CAT, old injectors, or a bad MAF.

My car develops a very slight stumble (loss of power) only at 50mph and accellerating lightly. It runs great at WOT and below 50mph. I have an A4. The BLM's shot up to 160 when i was scanning showing that the car was running lean when this occured.

Any idea what this may indicate? is it related to my stumble?
Basically, Would the EGR cause this or would these symptoms be more related to the CAT, old injectors, or a bad MAF.