You could try leaning the idle mix a little and make sure the air cleaner and pcv valve is good.
Grams Per Mile testing takes into consideration all aspects of driving, idle, accel, cruise and de-cell. Kinda hard to trouble shoot without idle and cruise readings.
Here in AZ, we have idle and cruise only, no "GPM". Makes pinpointing the problem a little easier.
As far as the NOX goes, you need to ck your EGR valve. You can get a piece of vac hose and hook it to the egr and start it up and suck on the hose. If it is working, it should open and the idle will go to crap and probably die. Some engines require some amount of exhaust backpressure before the egr will open though, not sure on yours.
If the EGR works ok, ck the timing, idle speed, plugs and wires, if all are ok, give it another try, it might pass this time.