US gas prices have rocketed higher during the on-again, off-again war with Iran.

After a brief respite, the average price for gas has surged 15 cents in a week to $3.94 a gallon and appears headed north of $4 again. Diesel, which shows up in customers’ shipping costs, topped $5 a gallon again Thursday for the first time in 3 weeks, according to AAA.

It serves as a painful reminder of how the military conflict in the Persian Gulf has a direct effect on your wallet.

But it’s not quite that simple.

Rising fuel prices aren’t just a story about higher oil prices anymore. Gas and diesel prices have taken on a life of their own, divorced from whatever is going on in the Strait of Hormuz and America’s ability to extract concessions from Iran.