After a streak of mostly stable fuel prices in Iowa, drivers began to feel even more pressure at the gas pump over the last week. According to the Iowa Department of Agriculture and AAA-Iowa, the price for a gallon of regular unleaded gasoline averaged $3.92 as of Wednesday, May 4. That is a six-cent rise from last week and a $1.13 higher than this time last year. The national average climbed 10 cents to $4.23 per gallon. Diesel prices experienced a sharper change, jumping 42 cents to $5.28 per gallon. Last year, diesel in Iowa averaged just $3.02 per gallon. The national average outpaced Iowa prices by 15 cents at $5.43 per gallon. Wholesale ethanol was unchanged at $2.16 per gallon. Natural gas was up 96 cents at the Henry Hub reporting site to $8.32 per MMBtu in the heating fuel market.