When your 2022 Chevrolet Colorado displays the P0305 code, the engine control module has detected repeated misfires in cylinder 5. The 2022 Colorado (final year of the second generation) offers the 2.5L four-cylinder, 3.6L V6, and 2.8L Duramax diesel. P0305 is valid only on the V6, which has cylinders 1-6.
Engine Identification
Verify your engine configuration before proceeding. The 2.5L I-4 and 2.8L Duramax diesel both have only four cylinders—P0305 would be anomalous on these. The 3.6L V6 (308 hp) is the configuration where P0305 indicates a legitimate misfire.
Cylinder 5 Location
On the 3.6L V6, cylinder 5 is positioned on the rear bank toward the firewall. GM places odd-numbered cylinders (1, 3, 5) on the rear bank for this transverse-style V6 installation.
Common Causes
Spark plug wear is likely if approaching service interval. Ignition coil failure at cylinder 5 is possible. Direct injection carbon buildup on intake valves accumulates over time. Fuel system issues including high-pressure fuel pump or injector problems can cause lean misfires. Vacuum leaks near the intake manifold affect individual cylinder performance.
Diagnostic Steps
Confirm V6 engine installation. Read all codes and freeze frame data. Access cylinder 5's spark plug and inspect condition. Test the ignition coil through resistance check and swap testing. Look for vacuum leaks. Review maintenance history for spark plug replacement intervals.