98 5.7L Vortec 2wd STUMPER - P0420/430 Persistant

[shultzee13]

Both cats replaced with new.
All four (4) 02 sensors replaced with AC Delco AFS105 and AFS106 sensors.
No exhaust leaks.
No other codes.
Had engine grounds cleaned, no change.
Clear codes, drive, they comes back.
Have performed PCM reset.

Brand new AC delco spark plugs, wires, cap, rotor, even distributor. Yes I replaced the distributor and the cam shaft sensor.


Without spending an arm and a leg, is my ONLY option to buy the spark plug defoulers and trick the computer?
I notice quite a bit of difference in fuel economy with the computer throws the codes.
How do I determine if the PCM is at fault? maybe it's finally gone bad. I understand that is rare though. I can't figure it out.

Thanks
Eric