Here are my emissions results...

300TE /// Standard (grams per mile) /// Result

HC: 0.39 /// 1.60 /// PASS
CO: 5.42 /// 15.00 /// PASS
NOx: 2.85 /// 2.50 /// FAIL

Fuel Cap: FAIL


Would the fuel cap possibly attribute to the fail?

I have all the standard tune up items done ignition-wise (rotor, cap, wires) in the last 20k, new spark plugs in the last 5k and a rebuilt fuel distributor + flow matched EHA on the fuel side last month. Duty cycle is closed-loop around 50%. O2 sensor is about 15k old. I have a new High Flow Magnaflow Cat which is 3 years old now. Precats are hollowed out (passed CA smog with it last year).

Ideas? I get a free retest within 60days so I got some time to work through this.

EDIT:

PS: No EGR on my model.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k