P0420 25 miles after spark plug change

Tundra TRD Pro 2023. Got new spark plugs from dealer at 41K and got them replaced non dealership to keep emissiong warranty.
However after 25 miles or so of driving check engine light came on. Put in the code reader and its the P0420 on bank1

I thought maybe a plug is bad, but there are zero misfires.
What could be the cause? O2 sensor wiring? There are no O2 sensor codes.

 

Forget to plug in a coil? Didn't get the correct plugs? Didn't check gap on some plugs? Sounds a bit odd, but the code triggers over time, IIRC.

 

No misfires and no other codes. No loss of power. Brand new plugs. Could be a bad plug with bad gap I guess

 

Could be. The code is for catalyst threshold, meaning the O2 sensors were reading an exhaust irregularity. I wouldn’t think the catalytic converters are going out already (could be, but doubt it). So it’s either o2 sensors (also less than likely) or something going on with the air/fuel mixture. Since the plugs were recently replaced just before the issue started, I’d start there to verify gap and such.

Could be coincidence, but I’d also look for any bad wires from critters and such, especially around the o2 sensors.

 

Okay going to tech tomorrow. Hopefully techstream will be able to shed more light as compared to my el cheapo scanner

 

Went to the dealership where the tech works. Checked all connections, everything is hooked up. Cleared codes and ran all tests from Techstream, all voltages etc., within parameters. Even ran the advanced tests. Have driven 25 miles + now. Last time code actually came after 14 miles. Will check again tonight by doing a drive cycle after the engine cools down. If it stays away for 100-200 miles I guess it should be okay.

I got this on my GX after I disconnected and reconnected battery and it never came again. Probably related to that. Not sure what funkyness is going on