2004 Chrysler Sebring 2.7L V6 OBD II P0300 Misfire: Diagnosis and Repair Guide
I own a 2004 Chrysler Sebring Limited Convertible with a 2.7L V6 engine. When the vehicle is cold, it triggers OBD II diagnostic code P0300, indicating a random misfire across multiple cylinders. The check engine light activates shortly after starting and either blinks or remains on. I suspect a short-term fuel trim issue. I've already replaced components including intake manifold gaskets, spark plugs, MAF and IAT sensors, crankshaft and camshaft position sensors, oxygen sensors, IAC valve, and catalytic converter #1. Despite these repairs, the problem persists. How can I accurately identify the faulty component and resolve this misfire issue? Any guidance or troubleshooting steps would be greatly appreciated.
Check fuel pressure and ensure there is no fuel pressure drop when the engine is off (KOEO). Use an OBD II scanner to review freeze frame data, including ECT temperature, fuel trim values, and oxygen sensor voltages. Also verify that this vehicle does not have a Mitsubishi engine—this may be a common confusion point.