...but also make sure the engine is COLD. High combustion chamber temps ususally cause the NOX to raise.

There's a barrage of tricks you can try, and combining them all together should make sure you pass.

Flush the engine with an engine cleaner, as well as the fuel system, and change the oil. Your HC and CO are low, so you could run a lower weight if you wanted. Get spark plugs 1 heat index cooler than your current plugs. Drain the coolany and add 100% water with 2 bottles of Redline Water Wetter. Unfortunately, I'm not sure how to make it so the mechanical fan stays on the whole time (I've always had electrics so I just switched them on). Double check your ignition timing (though they probably did that on your first attempt, so you know if it's on or not).

That should be enough to pass you. Our trucks are notoriously high with NOX readings from posts I've seen in the past. Those tricks worked for me last year. Let's see if they work again this year! <img src="/forums/images/graemlins/coolg.gif" alt="" />