I've owned my Nissan Patrol 2019 model for about three years now and I know these cars are not exactly known for being fuel efficient, they're big heavy machines and I accepted that when I bought it. But something has changed in the past couple of months and I'm trying to figure out what's going on. I used to get around 550 kilometers from a full tank of petrol when driving normally around Abu Dhabi, mostly city driving with some highway. But lately I'm lucky if I get 450 kilometers from the same full tank, sometimes even less. I haven't changed my driving habits, I haven't added any heavy accessories to the car, and there are no warning lights on the dashboard. The car still drives fine, no strange noises or smells, but I'm filling up so much more often and it's starting to hurt my wallet. I asked a friend who knows more about cars and he suggested it could be anything from dirty spark plugs to a clogged air filter to a faulty oxygen sensor. He said I should find a proper Nissan repair service in Abu Dhabi that can run a full diagnostic instead of just guessing. Has anyone else experienced a sudden drop in fuel economy on their Patrol or any other Nissan model? What ended up being the cause and how much did it cost to fix? Could it be something as simple as underinflated tires or old engine oil, or am I looking at a more expensive problem like a failing fuel injector or sensor? I really don't want to just start replacing parts randomly hoping something works, I want someone to actually figure out what's wrong. Also, is there anything I can check myself before I take it to a mechanic, like cleaning the air filter or checking the tire pressure? Any advice from fellow Nissan owners would be really helpful because I'm tired of spending so much money at the petrol station every few days.