A P0303 code in your 2020 Chevrolet Colorado indicates the engine control module has detected repeated misfires at cylinder 3. This midsize pickup truck offers three engine options: the 2.5L four-cylinder, the 3.6L V6, and the 2.8L Duramax turbo-diesel. Each engine requires specific diagnostic considerations, making engine identification the first step in troubleshooting.
Cylinder 3 Location by Engine
The 2.5L inline four-cylinder places cylinder 3 third from the front of the engine. The 3.6L V6 positions cylinder 3 as the middle cylinder on the driver's side bank. The 2.8L Duramax diesel is also an inline-four, with cylinder 3 third from the front. Understanding your engine's configuration ensures accurate component identification.
Gasoline Engine Considerations
Both the 2.5L and 3.6L gasoline engines use traditional spark ignition with direct fuel injection. Common P0303 causes include spark plug wear, ignition coil failure, and fuel injector issues. The 3.6L V6 also features variable valve timing, which can contribute to misfires if timing chains stretch or solenoids fail.
Diesel Engine Differences
The 2.8L Duramax diesel doesn't use spark plugs—it relies on compression ignition. P0303 in this engine indicates combustion irregularities from fuel injector problems, glow plug issues (cold starts), fuel pressure problems, or compression loss. Diagnosis differs fundamentally from gasoline engines.
Age-Related Wear Factors
At approximately four to five years of age, the 2020 Colorado may experience wear-related issues. Spark plugs in gasoline engines may need replacement depending on mileage. Ignition coils degrade from heat cycling. Carbon buildup in direct-injected engines affects airflow. Fuel injector deposits accumulate over time.