Petrol is still a bit of an issue in Uzbekistan because they dont really have their own. what they do have is natural gas, and lots of it. So many cars in Uzbekistan have been converted to run on gas, like LPG cars in the west. In north west uzbekistan, it can be a real problem to find petrol. Up there is mostly gas. There are a few petrol stations in Nukus, but elsewhere in the Northwest either the fuel stations have no petrol (only gas) or they have very bad quality petrol. In places like Kungrad we managed to get the owner of the chaikhana we stayed at overnight to get us 30 litres of blue Turkmenistan smuggled "benzin" and used that. Generally you wont have a problem, you just have to make sure you fill up where you can, when you see it. And if you are desperate, ask around. Its legal. Price was only 50 eur cents. A little more than in neighboring Kazakhstan In the south of the country where the big cities are (Bukhara, Samarkand, Tashkent etc) there is no problem at all finding petrol.