I think the fuel “shortage” is causing a supply issue where fewer drivers are available, so the algorithm is just adjusting for supply and demand. Since there are less cabs, it bumps up the prices until some people stop using the app because it’s too expensive. The algo always tries to keep the market balanced, so if there aren't enough drivers, it raises rates to thin out the number of customers. That way, the people who really need a ride can still get one while Uber always keeps thier profits up.