Gov. Mark Sanford, backed by some state legislators, is pushing for a suspension of the state's gas tax, which is 16.8 cents per gallon, from October to December.
The move would save the average family about $63 over the time the tax is lifted, Sanford said.
But it would lead to a reduction in state revenues of about $134 million -- money that normally goes toward highway construction and maintenance.
Local legislators called the move election-year pandering.
"It's too much politics and not enough public policy," said Rep. Richard Chalk, R-Hilton Head Island.
The measure awaits Senate approval after passing through the House on Wednesday.
Chalk and fellow Reps. Bill Herbkersman, R-Bluffton, and Thayer Rivers, D-Ridgeland, voted against the amendment.
Reps. Catherine Ceips, R-Beaufort, and Kenneth Hodges, D-Green Pond, didn't vote on the measure and couldn't be reached for comment Thursday.
"I think it's a ridiculous idea," said Sen. Scott Richardson, R-Hilton Head. "We're all reeling from gas prices. But it's not about the gas tax. It's about supply and demand."
Sanford said the state's economy is growing fast enough that the cuts shouldn't affect road projects.
"We think it would have real bottom-line benefit to a lot of working families who are struggling with the price of gas," Sanford said at a recent news conference.
The state's gas tax is already the one of the lowest in the nation, in part causing under-funded road projects, Rivers said.
"It's shameless," he said. "This is designed to make people look good."
An original proposal supported by Sanford had the tax suspended during the summer months but was shot down after legislators said it would benefit too many traveling vacationers.
"I wouldn't mind giving a break to South Carolina residents," Herbkersman said, "but to give out-of-state residents a break is just ridiculous."
As gas prices spike to about $3 nationwide, other states have taken on the task of finding relief.
Governors have floated ideas to trim or suspend state gas taxes in Maryland, Connecticut and North Carolina. State legislators are pushing similar measures in New York, Connecticut and Nevada. None of the measures has become law.
On average, states add 28.1 cents to each gallon of gas from a combination of excise taxes, business taxes, and state and local sales taxes.
The federal government also adds 18.4 cents to each gallon.