Iowa gasoline prices took their biggest jump in the last month since August of 1990, before the Gulf War began. Iowans are now paying a dollar-38 on average per gallon, an increase of 17 cents from last month and 48 cents higher than February a year ago. Iowa Senator Chuck Grassley says the U-S should threaten to cut off its financial support to oil-producing nations.Grassley is appealing to the U-S Energy Secretary and to President Clinton to take steps that would put the squeeze on OPEC nations. He says if the leaders of those nations were American C-E-O’s, they’d be in prison for breaking anti-trust laws. Grassley says nations like Saudi Arabia shouldn’t be allowed into the World Trade Organization if they want to continue cartels.Diesel prices in Iowa are averaging a dollar-45. That’s 12 cents over last month and 43 cents higher than a year ago.