Senator Debbie Stabenow is urging both chambers of Congress to oppose an effort to change a jobs bill she wrote.
House Republicans want to cut $1.5 billion from the Advanced Technology Vehicle Manufacturing Loan Initiative.
It provides incentives to automakers to encourage them to transform old factories to build cars in Michigan.
The Department of Energy estimates the initiative has created or saved 41,000 American jobs.
House Republicans have attached their plan to funding for disaster relief for families devastated by recent tornadoes, hurricanes and other natural disasters.