Toyota quickly suspended sales of its 2010 Lexus GX 460 sport utility vehicle on Tuesday after Consumer Reports magazine warned buyers that the model had a dangerous handling problem that could lead to a rollover and possibly “serious injury or death.”

Toyota’s Lexus division withdrew the car just hours after the warning was issued Tuesday.

“We are taking the situation with the GX 460 very seriously and are determined to identify and correct the issue Consumer Reports identified,” Mark S. Templin, the Lexus group vice president and general manager said in a statement.

Lexus stopped short of voluntarily recalling the vehicle, but said it would provide a loaner car until a remedy is available to any concerned customers.

The National Highway Traffic Safety Administration said in a statement on Tuesday that it was in communication with Consumer Reports and Lexus. The agency’s files, as of Tuesday, showed no record of consumer complaints related to the 2010 Lexus GX 460.

A Lexus spokeswoman, Allison Takahashi, said the automaker was not aware of any “accidents or incidents related to this condition.”

A “don’t buy” warning is rare for Consumer Reports, but there was no doubt it was necessary, said David Champion, senior director of its auto test division. The litmus test was whether the testers would want their families in the vehicle. The answer was no, he said, so “I wouldn’t want anybody else in it.”

The handling problem arises if the driver of a Lexus GX 460 S.U.V. eases off the gas pedal while driving quickly through a sharp turn. That causes the rear end of the vehicle to slide toward the outside of the turn, a condition known as trailing throttle or lift-throttle oversteer.

On dozens of other S.U.V.’s tested by the magazine, the electronic stability control system of the vehicles detected and quickly stopped the slide. But the stability control did not stop the GX 460 until it was almost sideways, Mr. Champion said.

The government tests some vehicles for rollover risks, but the agency said Tuesday that it had not yet tested the Lexus GX 460. The agency said it believed that the electronic stability control should prevent the fishtail problem described. The agency urged drivers of the model “to use care and caution.”

The issue is yet another public relations problem for Toyota. In addition to complaints about unintended acceleration and Prius brakes, there have been questions over whether the automaker was prompt in reporting problems to safety investigators.

Most recently, the federal government said it was seeking a $16.4 million fine, accusing the automaker of not acting quickly enough. Toyota said that it was “considering a response.”

But this time, Toyota moved swiftly and without any prompting from the National Highway Traffic Safety Administration, federal safety officials said.

The agency did say it was “in the process of testing” the Lexus hoping to “better understand the results obtained” by Consumer Reports. The agency said it was working with the automaker and the magazine’s testers.

Lexus sold 4,787 GX S.U.V.’s in the first quarter of this year, Edmunds.com said. That represented 10 percent of Lexus sales and 1 percent of Toyota Motor Sales at the manufacturer level, Edmunds said. The GX 460 starts at around $52,800 with destination charges.

The last time Consumer Reports made a similar “don’t buy” warning was in 2001 for the 2001 Mitsubishi Montero Limited.

Mr. Champion said that the problem came to light at the magazine’s test track in East Haddam, Conn., while looking for “any nasty habits that might catch a driver out.” He said, “We want a car to be benign.”

The particular test that concerned the magazine involves a turn that suddenly gets sharper. The driver enters at about 60 miles an hour and then, as if surprised, lifts off the gas. Ideally, the electronic stability control would stop a slide caused by that maneuver, allowing the vehicle to safely complete the turn.

“I think it is more a calibration issue of the electronic stability control,” Mr. Champion said.

Four of the magazine’s drivers tested the Lexus without being allowed to watch one another or to compare notes, Mr. Champion said. They met later and discovered each had a similar problem with the tail sliding too far.

Mr. Champion said such a problem could happen in everyday driving. For example, a driver heading quickly through a turn — like a highway off-ramp — who finds the turn is sharper than expected would naturally lift off the gas, he said.

In an earlier statement, Lexus complained that the magazine had not demonstrated the problem for its representatives. Mr. Champion said, however, that on the day the officials visited the track, there was a hard rain, which would have made a precise duplication impossible. But, he said, they had shown the Lexus officials a video of their tests.

Mr. Champion said electronic stability systems used on other Lexus and Toyota models have always worked quickly to stop slides, so the problem on the GX 460 was surprising. The new Toyota 4Runner, which uses the same basic architecture as the Lexus, was tested the same day and did not have the problem.

In 1996, Consumer Reports said the 1995-96 Isuzu Trooper and the mechanically similar 1996 Acura SLX could roll over during quick turns at low speeds. Isuzu sued, charging the publisher, Consumers Union, with product disparagement and defamation. But a jury in Federal District Court in Los Angeles decided that Consumer Reports had not defamed and disparaged Isuzu.

A involving the Suzuki Samurai S.U.V. dragged on for eight years before Suzuki and Consumers Union agreed in 2004 to settle a dispute over the magazine’s assessment of the vehicle’s rollover risks. The case reached the Supreme Court, which in 2003 refused Consumers Union’s appeal of a lower court ruling requiring the organization to stand trial in the product disparagement suit brought by Suzuki.