What is the best way to maintain the performance of my Nissan Patrol engine?

I have a Nissan Patrol that I love to take off-roading, but I've noticed that the engine seems to be losing its power. I want to keep my vehicle running smoothly, so what steps should I take to maintain the engine's performance?

Regularly checking and replacing the spark plugs is crucial for maintaining engine performance. Make sure to also clean or replace the fuel and air filters as needed.

Don't forget to change the oil and oil filter at regularly scheduled intervals. Also, keep an eye on the coolant and make sure it's at the correct level.