Suggest to proceed to workshop for repair, usually the keypoints of diagnose are:
1. Check the car ignition system and start up circuit diagram.
2. Check if the spark plug still in good condition, replace if spoiled. Suggest to replace all spark plug at once because using a mixture of old and new spark plugs might cause engine vibration, weak acceleration and higher fuel consumption.
3. Check and tune the electronic ignition system, correct the advance or delayed ignition.
4. Start the car to check and tune all replaced part.