#2 cylinder misfire
Asked by GuruYWNZG Mar 22, 2019 at 10:41 PM about the 2005 GMC Envoy 4 Dr SLE 4WD SUV
Question type: Maintenance & Repair
Took to auto zone ran diagnostics
code po420 how do I determine which
of multiple reasons for misfire they
include; 1. Leakage into exhaust valve
guide seals spark plugs or wires. 3.
Coils
5 Answers
Sirkut_Interrupted answered 5 years ago
P0420 is not a misfire code is a catalytic converter inefficiency code
Yes tech says if I can figure out what is causing misfire catalytic converter code should go away. How do I go about figuring this out is it possible?
Sirkut_Interrupted answered 5 years ago
P0420 sets when the computer tests the oxygen storage of the cat. If this was a lean upstream exhaust code then id say yeah fix your misfires and they cld go hand in hand
For the I6 engine, you obviously have another code, P0302. Usually that will be your coil, swap coils with another cylinder and see if the misfire follows. Fixing P0302 won't get rid of your P0420, that code as explained above is for your cat.