Its definitely carb tuning. If its tuned right it will pass no problem. My old boss always used a cylinder balance analyzer for tuning. You can also use a wide-band O2 sensor. You could just try small changes on your own (lean it out), and just keep going back to DEQ for a free air-check (you don't have to do ay paperwork if you ask for the free air-check) until it passes.
The good thing about this all is you will stop wasting extra fuel once you get it tuned right. I just realized yesterday how big of a jump fuel prices made again:E