Pressure is rising on Speaker Nancy Pelosi (D-Calif.) to act in July on the contentious issue of raising Corporate Average Fuel Economy standards, despite the desire of House Energy and Commerce Chairman John Dingell (D-Mich.) to wait and tie it to a global warming package due in September.

Five Cabinet secretaries sent a letter to Pelosi last week applauding the Senate for passing higher CAFE standards and mandates for alternative fuels.

“We encourage you to address these important policies in the House July energy package too instead of considering them at a later date,” they wrote.

Many Democrats and environmental groups also are eager to seize on the issue, which has escaped Congressional action for two decades. There is little dispute on the need to raise the standards, but Democrats differ on how much and how fast.

Pelosi said Friday that the issue would be part of the September global warming package, but she did not rule out taking it up earlier either on the floor as an amendment or in conference negotiations with the Senate.

“The Congress will work its will. We have, as I’ve said on every issue, be it trade, taxes, the war, whatever, energy, we will always build consensus in our Caucus to the position we have,” she said. “None of these issues will cause a fissure in our Caucus.”

But keeping the Caucus together may be easier said than done.

Both Pelosi and House Majority Leader Steny Hoyer (D-Md.) said separately that they back language passed by the Senate that would increase CAFE standards to 35 miles per gallon for both cars and trucks by 2020, a level strongly opposed by the auto industry, which wants weaker standards for trucks in particular.

And Rep. Ed Markey (D-Mass.), who has led the charge for higher CAFE standards and chairs the Energy Independence and Global Warming Committee, has made no secret of his desire to see the issue passed as soon as possible. “The country has been waiting for twenty years to address this issue, and now that we are importing 60% of our oil, we cannot afford to wait any longer,” Markey said in a statement. “I intend to proceed with a strategy to ensure that the House matches the Senate’s action and includes a strong fuel economy provision in our summer energy package.”

Both Dingell and Energy and Air Quality Subcommittee Chairman Rick Boucher (D-Va.) said they have not received any assurances that leadership will not seek to add CAFE to their legislation on the House floor, although Dingell has said he would oppose such a move.

Nadeam Elshami, a spokesman for Pelosi, said that the question is simply one of timing, not substance.

“The Speaker has said that she supports CAFE standards and will act on CAFE standards,” he said.

Elshami also noted that the Bush administration has had six years to work on energy “and they failed.”

“Anything that an oil and gas administration such as the Bush administration says should be taken with a grain of salt, but we will work with Republicans to get a bill to the president that will end our dependence on foreign oil and reverse global warming,” Elshami said. “The new direction Congress will lead the way.”

Dingell and Boucher had drafted more lenient CAFE standards than the Bush administration had offered and had proposed to prohibit states and the Environmental Protection Agency from regulating greenhouse gas emissions from vehicles.

Pelosi rejected their plans, so Dingell and Boucher dropped the controversial language for now. They also postponed other controversial issues, including coal-to-liquids technology and nuclear power provisions, which Dingell said would be considered later.

The Bush administration also is seeking a doubling of the Strategic Petroleum Reserve to 1.5 billion barrels and an expansion of oil and gas drilling. But pro-drilling in initiatives have far less support among Democrats.

“We’re not going to drill our way out of the energy crisis,” Elshami said.

Jennifer Yachnin contributed to this report.