How can I maintain the performance of my Ford Focus's engine?

I have been driving my Ford Focus for a few years now and I have started to notice a decrease in its performance. What can I do to maintain the engine's performance and keep it running smoothly?

Regularly changing the oil and oil filter is crucial for maintaining the engine's performance. Also, make sure to check and replace the air filter as needed. These simple steps can greatly improve the engine's performance.

Another important factor is to keep an eye on the spark plugs. They can wear out over time and affect the engine's performance. Replace them every 30,000 miles or as recommended by your vehicle's manual.