Gen 7 Problems/Service Issues/Troubleshooting
I have a 2009 malibu with the 2.4 4cyl engine. I've gotten the 420 code again. I replaced oxygen sensors but still receive the 420 code. The kicker is I've replaced the exhaust manifold/cat 2 times already. The car runs perfect. Doesn't burn oil, no coolant leakage nothing except this damn cat...