NEW YORK, MAY 26 -- Jane Amsterdam, editor of the New York Post, has been forced out of her job by publisher Peter Kalikow, who complained to her that the tabloid's more respectable brand of journalism wasn't making money, according to sources at the newspaper. The ouster of Amsterdam after less than 12 months follows the virtual collapse of the Post's new and much-ballyhooed Sunday edition, as well as a dispute over whether to publish a critical story about a developer friend of Kalikow, the sources said. Amsterdam, 37, former editor of Manhattan, inc. magazine and a onetime editor at The Washington Post, technically resigned late Thursday, although the tabloid has made no announcement. Sources say that New York Post columnist Jerry Nachman, 43, a former vice president of WRC-TV in Washington and a former news director at WNBC-TV here, has discussed the editor's job with Kalikow and is considering it. Amsterdam was described by sources as deeply disappointed by Kalikow's sudden decision to replace her in the $200,000-a-year job. She was a popular figure among many in the South Street newsroom, and as recently as March she had been working enthusiastically with Kalikow as they launched the first Sunday paper, which was celebrated with champagne. According to sources, Kalikow told Amsterdam that the paper had become "credible" during her tenure, but that "credible doesn't sell ... Your big scoops are great, but they don't sell more papers." The publisher said he wanted to take the Post in a new direction, one presumably closer to its sensationalist roots, the sources said. Kalikow, 46, a bombastic real estate developer who bought the paper from Rupert Murdoch last year for $37 million, is described by some Post employees as an impulsive boss who has made a series of risky decisions, including raising the paper's weekday price to 40 cents and starting a $1 Sunday edition, which he vowed he would back for as long as it takes. Yet after just 11 weeks, Kalikow has drastically scaled back the Sunday venture, dropping the travel, television, magazine and book review sections in favor of a one-section, 40-cent paper. Amsterdam's ouster, after several heated disagreements, came just as suddenly. "If there was a failing in Jane, it was management," said one person close to Kalikow. "She couldn't manage. That was her undoing. He was not satisfied with some of the things she was doing ... I think she was a little over her head." This person said that Amsterdam had little feel for political news and had trouble delegating authority. He said she often worked 14-hour days and resisted suggestions that she hire a strong deputy. One clash erupted when Kalikow, who repeatedly promised not to interfere with news decisions, tried to block a story about a rent strike at a luxury Upper East Side high-rise owned by a friend, Sheldon Solow, sources said. At Amsterdam's insistence, the story, detailing complaints about roaches, leaking toilets and buckling floors from tenants paying as much as $5,000 a month, ran this week. The Kalikow associate said it was "a nonstory" because the complaints about Solow's building had already been reported in a local magazine. In fact, he says, "she's published stories that have knocked friends of his for a year, including {Sen. Alfonse} D'Amato and {Donald} Trump," he said of Amsterdam. "Anyone who goes through the clips will find 10 of Peter Kalikow's close friends who have been roasted by the Post." Another dispute involved Amsterdam's decision to kill a column by Pete Hamill that criticized a Post story on a new biography of Jacqueline Kennedy Onassis. Amsterdam spiked the column because Hamill was once a frequent escort of the former first lady. The columnist, who did not get along with Amsterdam, left the Post shortly afterward, and some blamed her for Hamill's departure. Yet another argument erupted over Kalikow's attempt to hire George Arzt, a former Post reporter who has been press secretary for Mayor Edward Koch for the last several years. Sources say Amsterdam blocked the hiring on grounds that a Koch aide should not be hired in the middle of a mayoral campaign and be expected to cover politics objectively. These and other incidents left Kalikow complaining that "it's my paper" and that he should be able to run it as he saw fit, the sources said. Post staffers are sensitive about their independence because of the paper's recent history. In journalism circles, the paper is viewed as vastly improved over the days when Murdoch used the news columns to promote political friends such as Koch, whom he virtually drafted for a 1982 race for governor, while attacking opponents such as Sen. Edward M. Kennedy (D-Mass.). With a daily circulation of 550,000, the feisty, occasionally erratic paper is struggling in the nation's most competitive media market. The Sunday edition, which won plaudits for its editorial content, is nevertheless said by competitors to have lost at least $6 million, and sales have dwindled to about 200,000. Kalikow, who is worth an estimated $500 million, has blamed the poor Sunday showing on his inability to obtain the popular coupon inserts already offered by The New York Times, Daily News and Newsday. Sources say that two coupon companies owned by Murdoch refused to provide the inserts to the Post, although the paper offered to carry them without charging the customary fees. Amsterdam's departure follows last month's resignation of Post publisher Peter Price, who quit to join a distributor of television programs. He was replaced by Valerie Salembier, a former publisher of TV Guide, who was given the title of president. Nachman, the acerbic columnist and onetime radio reporter who is Amsterdam's likely successor, has grown close to Kalikow in the past year and has praised his stewardship. Amsterdam, who is married to Village Voice Editor-in-Chief Jonathan Z. Larsen, was widely credited with turning Manhattan, inc. into a fast-selling, award-winning magazine after she helped launch it in 1984. She resigned from the magazine in March 1987 after accusing owner Herb Lipson of trying to interfere with editorial content and insisting that she meet with potential advertisers.