Just wanted to get some opinions from you guys, and yes I have read every single post referring to this issue in the search function. I have had both heads rebuilt 20k miles ago and engine serviced as well and a new catalytic converter was installed at the same time.

I failed three weeks ago in the 15mph NOX but passed in the 25 mph NOX. This was all I failed.

I was told to try cleaning the EGR and/or replace the Catalytic Converter. I look the cheaper route and ordered the gaskets and removed and cleaned the EGR and EGR intake tube myself. After some stuck/sheared bolt problems the EGR was put back on and I ran some fuel system clear through the gas tank. The tank was almost empty when it was tested the second time.

Retest results:
15 mph
NOX
from 1200 to 2400 ppm
Max 900

25 mph
NOX from 700 to 2900 ppm
Max 900

And all the other measurements went up slightly but not enough to worry about.

Other considerations at this time is replacing the Oxygen sensor as I have pinging at low rpms and have been told I am running lean. Also, the muffler shop has told me my EGT's are hot and I am slowly cooking off coolant, but the engine temps are low.

Thought?
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