Good morning,
420 is bank 1 catalytic converter is no good. It is no longer processing the gases from the engine. It has to be replaced.
https://www.2carpros.com/articles/catalytic-converter-replacement
As far as the misfire, I would check the fuel pressure and make sure the pressure is correct. Low pressure is common for misfire and 300 codes.
https://www.2carpros.com/articles/engine-misfires-or-runs-rough
Fuel Pressure (Key ON, Engine OFF) .................... 385-425 kPa (55-62 psi)
Roy
Catalytic Converter Replacement
Removal Procedure
imageOpen In New TabZoom/Print
1. Raise and suitably support the vehicle.
2. If equipped, unclip the oxygen sensor connection from the floor reinforcement.
3. Disconnect the oxygen sensor electrical connector.
imageOpen In New TabZoom/Print
4. Remove the oxygen sensor clips from the frame.
5. Disconnect the connector position assurance (CPA) retainers.
6. Disconnect the oxygen sensor electrical connectors.
imageOpen In New TabZoom/Print
7. Unclip the oxygen sensors electrical connectors from the following:
- Hose clip
- Transmission crossmember
8. Disconnect the CPA retainers.
9. Disconnect the oxygen sensor electrical connectors (1, 2).
imageOpen In New TabZoom/Print
10. Remove the left exhaust manifold pipe nuts.
imageOpen In New TabZoom/Print
11. Remove the right exhaust manifold pipe nuts.
imageOpen In New TabZoom/Print
12. Remove the exhaust muffler nuts.
13. Remove the catalytic converter.
imageOpen In New TabZoom/Print
14. If necessary, remove the oxygen sensors.
Images (Click to enlarge)
Mar 11, 2021 at 9:15 AM
