The Texas Legislature has considered bills to increase the gasoline tax twice (2001 and 2007) in the past 8 years. The bill failed to be passed in 2001 and the 2007 bill is currently referred to Transportation & Homeland Sec. The Texas gasoline tax has remained a static 20 cents per gallon since 1991.
http://www.legis.state.tx.us/BillLookup/History.aspx?LegSess=80R&Bill=SB165
http://www.legis.state.tx.us/BillLookup/History.aspx?LegSess=77R&Bill=HB3106

State Legislative Update (05/16/07) -- “With pump prices surging toward $3 and possibly beyond this summer, the Texas House voted by a wide margin Tuesday to temporarily save motorists 20 cents a gallon every time they fuel up. State senators also must vote for the measure before it can land on Gov. Rick Perry's desk. And they don't seem quite as enthusiastic. Lt. Gov. David Dewhurst said the suspension of the gasoline tax isn't a done deal, "particularly at a time when we're trying to find more resources to build highways and reduce congestion." The amendment to a gas-tax collection bill would repeal the state's gasoline tax for 90 days, which would cost Texas an estimated $500 million to $700 million toward highway construction and public education. But the proposal would make up for it by sapping the $8 billion budget surplus, currently split almost evenly between money set aside for future school property tax cuts and the state's Rainy Day fund. Houston Chronicle 5/9”