The ''big three'' automakers in the US, General Motors Corp, Ford Motor Co and Chrysler Group, are lobbying the Congress to dilute a major initiative on stricter fuel-efficiency standards, which they have been resisting for years.

The major proposal by the Senate would require automakers to introduce a 4-per cent improvement in fuel economy every year beginning from 2011. The proposal envisages vehicles to yield an average 35 miles per gallon by 2020

They believe the Congress is out to punish them for having stymied its efforts in the past to introduce new fuel-efficiency standards.

Last week, the chief executives of GM, Ford and Chrysler lobbied Democrat and Republican leaders to highlight their sales pitch that the US industry is still vitally important to the US economy despite losing market share to foreign rivals, most notably the Japanese and Koreans, and as such deserves special consideration.

Commentators say that the US auto industry continues to be relevant despite its sliding market share, and has always enjoyed special treatment on mileage standards. Consequently, now that the government wants it to be more efficient to reduce oil consumption, it finds it is unable to produce more fuel-efficient vehicles.

The strides in engine technology have gone in to increasing horsepower instead of mileage, they aver.

Some senators, sympathetic to the industry, are planning an alternative propose to mandate 36 miles per gallon for compacts, sedans and station wagons by 2022 and 30 for sport utilities, light trucks and vans by 2025, aproposal backed by the auto industry, including Japan''s Toyota Motor Corp.

But, a Ford senior executive believes that the proposal would break the industry, saying that there was nobody who could reach that target.