Hey all, I have a 06 Silverado 1500 with lq9 swap, I have stock exhaust and ever since I put my wideband in it has been reading all over the place, I put it in on driver side behind the cat, I'm getting a p2001 Nox trap efficiency below threshold code that nobody can explain.

I think I may have a bad cat, My wideband will be around 14.4-14.6 most of the time, then it will suddenly creep to 16.1-17 area then go back, just normal driving, and its very slow to react when I give it gas.

I figured it was a bad wideband sensor so I bought another one and same issue, I performed a sweep with my wideband and some brake cleaner and it went right to 10.0 then back to full lean when I removed the rag with brake cleaner.


Would a clogged cat cause these issues? Truck sat for a year before I bought it in a barn. I removed exhaust system when I installed motor and new trans.

before all of this the truck ran fine no codes, had a l33 with 3.42 gears and could still squak the tires if I mashed it, after the swap it could as well, now I punch it and it goes, doesn't squak tires, I believe it should considering the 6.0 has a cam as well.

thanks for any info.

 

A wideband MUST be installed before the cat converter.

They even say that in the direction included with any wideband.