A key battle will be a proposed increase in vehicle fuel-efficiency standards. Backed by powerful Detroit automakers such as Ford Motor Co. (F), DaimlerChrysler (DCX) and General Motors (GM), Rep. John Dingell, D-Mich., won a crucial skirmish last month when higher fuel standards were dropped from the House energy bill. The Senate, however, has backed tougher fuel standards, which could prevail if Dingell is outnumbered by influential lawmakers who support fuel efficiency.