2015 Tahoe P0430 Code

[Jeadding]

Hello, I’m new to the group. I’ve got a P0430 code I’ve been fighting with for a few months now. I took the car to an exhaust shop and they replaced the upper Cat on the passenger side, and both lower 02 sensors. The Cat that was put on was not an OEM. Not sure what kind offhand, but the guy at the shop said it was made for the vehicle. I’m not sure what 02 sensors he used either, I’ll have to take one out and see. The cat that was installed, came apart and I took it back and they welded the pipe and the cat back together. After about an hour of driving the code came back. I took the car to the dealer and they wanted 4K to put a OEM upper cat back and replace the 2 lower 02 sensors since we didn’t know off hand what kind they were. After that, they would trouble shoot if the code was still there. I just took the car home. Anyways, the code keeps coming back. I just replaced the upper 02 sensors, with OEM sensors, code came back after a few miles. I’ll check the lower sensors to see what kind were installed. Should I put an OEM upper cat on or should I start looking somewhere else? I don’t hear an obvious exhaust leak, car runs fine. My buddy said his older suburban had a bad intake gasket, which made all is cats /o2 sensors go bad. I’m trying to get ahead of it. Thanks In advance for any guidance. I’m not a mechanic, but like working on my cars.

 

[Jeadding]

So I did a scotch whisky cigar test to check for an intake leak, then sprayed some starter fluid around, no smoke being drawn in, and no change in the motor running, I’m thinking no intake leak.