Ford may still take part in a vehicle industry lawsuit over California's new clean-air law, surprising state officials who thought chairman Bill Ford was willing to cooperate with them, Reuters reported, citing the Wall Street Journal online edition.

Reuters said that the Washington trade group representing Ford and most other major vehicle makers said it expects to file suit against California regulators to try to block the new law, which makes California the first state to limit vehicle emissions of greenhouse gases, including carbon dioxide.

The law is due to take effect with 2009 model-year vehicles and would make vehicles run farther on a gallon of petrol, Reuters said, adding that the vehicle industry fears this measure will force them to re-engineer profitable but petrol-hogging sport-utility vehicles and pickup trucks.