The 2020 Lexus IS delivers sport sedan performance with choice of powertrain options. When your IS displays a P0304 code indicating a cylinder 4 misfire, understanding your engine configuration helps target accurate diagnosis.
Understanding P0304 in the IS
The 2020 IS offers the 2.0L turbocharged four-cylinder (IS300 RWD) or 3.5L V6 (IS300 AWD and IS350). For the turbo four-cylinder, cylinder 4 is at the rear of the engine. For the V6, cylinder 4 is on the rear of the left bank. Both use individual coil-on-plug ignition.
Age-Related Considerations
At this age, your IS may have accumulated mileage where component wear becomes a factor. Spark plugs may be approaching service interval. Ignition coils can develop issues after years of heat cycling. Turbo models may have carbon buildup on intake valves.
Diagnostic Approach
Identify your engine and access cylinder 4 accordingly. Inspect spark plug condition. On turbo models, check for boost leaks and consider carbon buildup. On V6 models, verify no vacuum leaks exist.
Repair Strategy
Replace spark plugs with Lexus specifications if worn. Test ignition coil output. On turbo models, intake valve cleaning may be warranted on higher-mileage vehicles. Verify fuel injector operation.