joeybrioso

Yes I use oem parts. No codes at this moment.

So I have a 2018 Tahoe 5.3 6sp with 85k. I bought it with 55k used from dealer. When I looks at the maintenance record it shows that the cat was replaced cuz p-0420. Now I’m trying to figure out what cause that code. During cold star ups and normal operating conditions I currently have a rough idle in park and and at stop lights but runs great when driving. I’ve been trying to find what is making this happen. I’ve been to 4 other dealerships in my area many different times and they can’t solve the issue during my warranty period. One dealership even replaced the engine and transferred all the old parts to the block . Still same issue. I have no codes , no air leaks, I replaced plugs , wire, coil, map, maf, pvc, fuel pump, evap, etc. fuels trims are ok and I’m getting the same results in the fuel balance test. Bank 1 is lower than bank 2. My cat temperature on bank 1 is 100 degrees hotter than bank 2 at idle and under load. I’m thing to replace the injector Now. Have you change yous ?

Any updates ?