A P0303 code on your 2017 Honda Accord indicates that the engine control module has detected cylinder 3 misfires beyond acceptable parameters. The 9th generation Accord featured different engine options than current models.
2017 Accord Engine Options
The 2017 Honda Accord (9th generation) offered a 2.4L four-cylinder producing 185 horsepower and a 3.5L V6 delivering 278 horsepower. These naturally aspirated engines differ from newer turbocharged designs.
2.4L Four-Cylinder
The Earth Dreams 2.4L uses direct injection and is known for good reliability. With four cylinders, each contributes 25% of power. Cylinder 3 misfires create noticeable rough running.
3.5L V6 Analysis
The V6 offers smooth, powerful performance. In a V6, cylinder 3 is located on one bank. Bank-specific issues should be considered along with individual cylinder components.
Higher Mileage Considerations
2017 Accords have accumulated significant mileage by now. Normal wear items may need replacement. Carbon buildup on direct injection engines becomes relevant at higher mileage.
Proven Reliability
Both engines have excellent track records. Address misfires to maintain the dependability these engines are known for.