The City Council’s fiercest critics of congestion pricing say that defeating the plan has become an uphill battle in the face of a formidable lobbying effort by Mayor Bloomberg and an endorsement by Governor Paterson.

“You certainly always have to give the mayor and the speaker, when they’re on the same side, the odds as to whether something is going to pass,” one critic, Council Member Lewis Fidler, said yesterday.

A little more than two weeks ago, a New York Times survey found nearly 2-1 opposition to the mayor’s congestion pricing plan among City Council members. Mr. Fidler was quoted as predicting: “It’s going to go down.” Days later, the scandal that led to Governor Spitzer’s resignation threw the mayor’s proposal into further uncertainty. After being sworn in, Mr. Paterson hesitated to endorse congestion pricing, and questions surrounding his marital relations further distracted attention from Mr. Bloomberg’s efforts to rally support for the plan.

Since then, however, there are indicators that Mr. Bloomberg may have steadied the ship. Over the past week, the mayor has aggressively used the bully pulpit to showcase transportation improvements, such as expanded express bus service and new traffic signal technology, that he says hinge on the passage of a congestion pricing program. A working draft of congestion pricing legislation also included concessions to the plan’s critics on two issues, residential parking and dedicating revenue from the program exclusively toward transportation improvements. Mr. Paterson’s declaration of support for congestion pricing over the weekend offers a strong boost to Mr. Bloomberg as he tries to sway lawmakers to his cause.

“It seems we had the momentum against it a couple weeks ago,” another congestion pricing critic, Council Member David Weprin, said yesterday. “I think there’s been a lot more lobbying since then and there’s a lot more money being spent on the pro-congestion pricing side.”

The mayor’s office has been working hard to gain undecided legislators’ support with guarantees of transportation projects specific to their district, and congestion pricing opponents say Mr. Bloomberg and Speaker Christine Quinn’s influence may be too much to overcome.

“How many of the people who are opposed will still vote no if the speaker starts leaning on them? I think that’s the key more than any of the issues,” another congestion pricing opponent, Council Member Tony Avella, said in a recent interview.

The council will debate congestion pricing at two hearings today in City Hall. Supporters and opponents alike say that the question of how much New Jersey residents pay to drive into the city and concessions to low-income commuters are likely to be the strongest remaining obstacles to the legislation’s passage.

The congestion fee on New Jersey commuters would be refunded against their bridge and tunnel tolls, meaning they would pay no additional money to enter the city were congestion pricing to pass, while New York drivers would pay $8. Twenty-one council members wrote a letter to the mayor last month asking him to include in congestion pricing legislation a way to ensure that New Jersey commuters pay a greater amount toward city transportation improvements.

Mr. Bloomberg has said he is exploring solutions to the problem, but that charging New Jersey residents more than New Yorkers to enter the city is unconstitutional. One possible compromise could be an agreement with the Port Authority, which collects bridge and tunnel tolls for New York and New Jersey, to contribute a certain percentage of its revenue to the Metropolitan Transportation Authority for mass transit improvements. Mr. Bloomberg has indicated he is also willing to find ways to refund certain low-income drivers some amount of their congestion pricing fees, another issue raised by lawmakers.