SACRAMENTO, Calif. — California’s governor has asked the attorney general to investigate why the state’s gas prices are so high, pointing to a new report suggesting big oil companies are “misleading and overcharging customers” by as much as $1 per gallon.

The U.S. average retail price of diesel fuel rose 2.9 cents to $3.133 a gallon as the benchmark West Texas Intermediate crude oil price closed at $68.93 a barrel April 23, a jump of $5.92.

The U.S. average retail price for diesel jumped 2.3 cents to $2.996 cents a gallon, the U.S. Department of Energy reported, while crude hovered near $62 a barrel amid political tensions in Iran and a decline in active U.S. oil wells.