The Trump administration is said to be pushing for 2020 limits to apply through 2026.

The Trump administration is reportedly considering a delay in implementing tighter fuel-efficiency standards.

The Department of Transportation is working on a proposal to simply freeze Corporate Average Fuel Economy requirements at 2020 levels through 2026, potentially averting a showdown over rumors that mpg thresholds would be "rolled back," according to Reuters.

If left unchanged, the regulations defined under the Obama administration will require automakers to hit a lofty CAFE goal of 54.5 mpg by 2025. As consumers shift toward SUVs, automakers have ramped up lobbying efforts to lower the targets.

California has reemerged as a wildcard, threatening to reintroduce tighter state-level regulations if the federal government unwinds the Obama-era rules.

The Trump administration is said to be meeting with California officials and automakers to negotiate a resolution to the simmering disagreements.