The P0302 trouble code on your 2018 Mazda CX-5 indicates that cylinder 2 is experiencing misfires detected by the engine control module. The second-generation CX-5 is powered by the Skyactiv-G 2.5L four-cylinder producing 187 horsepower. At typical 2018 mileage, age-related factors may contribute to misfire conditions.
Skyactiv-G 2.5L at Higher Mileage
The naturally aspirated 2.5L uses direct injection with a 13:1 compression ratio—one of the highest for a gasoline engine. This design is sensitive to carbon buildup and ignition system condition. By 2018 mileage, maintenance items may be due.
Common Misfire Causes
By 2018 mileage, carbon buildup on intake valves may be significant. The high-compression design is particularly sensitive to deposits. Ignition coil degradation affects spark delivery. Spark plug wear reduces ignition energy. Vacuum leaks from aged components develop.
Symptom Recognition
The compact SUV displays rough idle, vibration, and hesitation with misfires. Skyactiv's smooth character suffers. Check engine light accompanies the condition.
Repair Solutions
Replace spark plugs with Mazda-specified iridium units. Replace ignition coils as needed. Clean intake valve carbon if significant buildup is found. Address vacuum leaks. The high-compression engine responds well to proper maintenance.