Failing Emissions(95 lexus sc300)

Well, it seems like I spoke too soon in the off-topic emissions thread and I failed again ha.

Sc300 na auto

02 sensors are all newish and magnaflow universal cats newish also. Timing 14* advanced, newish OE spark plugs. No vacuum leaks that I can find, no current exhaust leaks. I failed by such a small amount I am not ready to rip the magnaflows out at this point. Running 91 octane, no over heating issues or any drivability problems.

I took it in for emissions first of the month.

Results / Standards
HC: 0.79 / .8
CO: 2.65 / 12.0
NOX: 4.61 / 2.0

Found a big exhaust leak at the manifold to downpipe, fixed that and failed again
HC: 0.45 / .8
CO: 4.59 / 12.0
NOX: 2.06 / 2.0

Failed by .06 on NOX, ugh!

A friend suggested retarding the timing a lot and try again. I dropped the timing back to about 6-8*.

HC: 1.01 / .8
CO: 3.55 / 12.0
NOX: 3.41 / 2.0

Now, should I step the timing back to the stock 10* and try again, advance it a little above 14*? It seems I was so close with it at 14* its so irritating. I've already spent more in emissions testing fees than the registration costs me.

On another forum someone suggested a faulty fuel injector. I hadn't thought about that before but its starting to make sense, maybe. I've had a small drop in MPG but I've been attributing it to the exhaust leak. I do have a 'tick' coming from the injector area but never thought much of that since every toyota I've worked on has sounded like a sewing machine at idle but it could be pointing at the injector.

I plan to pull the plugs and inspect them and go from there before attempting to retest.

Any further advice would be greatly appreciated. This car has been the one vehicle in my mini flee that has always given me emissions problems every single time I have to test it. Hasta

Is your car equipped with a PCV valve? Maybe the egr system just needs a cleaning. When bringing the vehicle in to be checked, is it at operating temps?

Running rich, might have leaky injector

Tried maybe running some acetone, other type FI cleaner? Have access to a Yota or Universal scan tool?

Thanks for the input guys.

I got it up to temp with a 'spirited' freeway ride before testing, kept the engine warm while waiting in line(I try and go when its not busy but its not an exact science so waiting does happen but I rev the engine). 2 Years ago it was failing and I ended up cleaning and replacing the EGR valve and related systems, turned out to be an exhaust leak then too that once fixed passed with flying colors.

Its pre obdII and no check engine light. I checked for codes using the old toyota paper clip trick and there is no codes.

I run a bottle of Techron through with each oil change but nothing more than that, I try and use quality gas always.

I've been leaning more towards the Injector being an issue, hopefully just one being faulty. I still plan to pull the plugs(replace since they are out) and oHm all the injectors and see what they show.