I have another post going.

https://www.thirdgen.org/forums/tech...sions-nox.html

I failed to high on NOX, A buddy of mine asked if there was a chip in the, not sure if the prev owner put one in. So I pulled the comp and it has a hypertech chip in it. It's a street runner chip pt no 121321

It says the idle/part throttle isn't affected so emissions and fuel economy aren't changed. 49state legal though, so why not able to use in cali if it doesn't alter emissions?

I am assuming advanced timing from the chip would cause my nox issue? I have already pulled the chip and want to run it through again, just want some other thoughts/reassurance. This damn car with it's emissions crap is driving me insane.

 

I removed the chip and went through again. All things being the same except ambient temps (slightly cooler) Nox went from 2.81 with the chip to 2.59. So maybe it had a small effect. Definitely not the root cause of failure.