Fueling up just got even more expensive. On March 31, the national average price for a gallon of regular gas climbed to $4.018, according to AAA, crossing a key threshold that tends to grab drivers' attention — and strain household budgets. It had been $3.99 on March 30. AAA data shows the national average stood at $2.98 a gallon on February 27, a day before the US and Israel bombed Iran. The gas price run-up has accelerated amid the heightened tensions in the Middle East. Shipping through the