"48 Hours" is an ambitious, provocative and accomplished prime-time news program that just doesn't work. It's had four weeks to hit its stride but still misses the mark. At this point, it's not even clear the mark is worth the trouble.

The weekly hour, produced by CBS News, is about to lose its Tuesday night time slot and will be moved to Thursdays, to the death zone opposite "The Cosby Show," starting March 17. That's the same pit into which ABC plopped its "Our World" nostalgic news show last year. It was canceled at the end of the season.

An identical fate may await "48 Hours." Its premiere, a portrait of two days in the life of Parkland Hospital in Dallas, scored a 12.1 rating and an 18 share in the Nielsens, not bad for a news series. But the numbers declined steadily in ensuing weeks, down to a 7.6 rating and 11 share for Tuesday night's "Inside the Promised Land."

That was the broadcast with, appropriately, the most promise, an attempt to delve deeper than usual TV news reports do into hostilities between Palestinians and Israelis in occupied territories of the West Bank and Gaza. There were intriguing and enlightening segments, and the program was not blatantly anti-Israel the way much news coverage (especially on CNN) has been.

But the show was not, in the end, as satisfying as it was frustrating. As with the first three shows in the series, segments start, then stop. Correspondents strut and orate. Dan Rather, anchor for all the episodes and working reporter on some of them, imposes his customary easy authority, but little else about "48 Hours" rises to his level.

In terms of production, the hour is mainly a series of interruptions -- bursts of clattering music and a spritz of graphics intrude on each segment to announce that a new one is beginning. The shows open with insufferable two-minute tease sequences of splashed-together clips orchestrated to the bleats and brays of some poor helpless synthesizer.

"48 Hours" seems to borrow from "West 57th" only the worst things about "West 57th," including the practice of billboarding reporters' names above the title of the show, as if they were movie stars.

The format for "48 Hours" was adapted from the successful and gripping CBS News documentary "48 Hours on Crack Street" that aired in 1986. It's video commando journalism: CBS sends in a SWAT squad of correspondents and camera crews to saturate a subject with two days and nights of intense taping, then edits the footage into an impressionistic whirlwind.

What worked on "Crack Street" doesn't cut it week after week. The programs, while containing plenty of superb footage, have been disjointed, fragmented and generally jangly. You may feel you're just watching a bunch of "Evening News" pieces strung together, then shown at a disco.

It's all so modular, it's NTV -- News Television.

The reports come complete with blabbing correspondents, who sometimes seem determined to get in the way. Bernard Goldberg is regularly assigned to the show and his work is supplemented by whatever other CBS correspondents can be rounded up. They figure if they're there, they should talk.

Most of them still don't know how to adjust their techniques for a news feature program; they speak in the same cliche's and bombastic tones they use for standard news reports. Bob Simon in particular appears to have no idea what's going on, declaiming loudly and stridently as if to a crowded convention hall. A program like this calls for the camera to be the chief correspondent.

The best segments have been those without excessive narration or reporter nudges: wading into clouds of billowing tear gas fired to disperse rock throwers outside a Coca-Cola plant on the West Bank; joining a grieving Hispanic family at the deathbed of a matriarch in Parkland Hospital; observing a procession of funny quickie weddings in the series' second program, "48 Hours in Las Vegas."

One couple got married wearing "Detroit Red Wings" sweat shirts. Another listened patiently to the clergyman reciting the vows and then pointed out to him that he had the wrong names for the bride and groom.

The Vegas show was the lightest of the four "48 Hours" programs so far (the third broadcast was about traveler travails at Stapleton Airport in Denver), but in some ways it was the best; the segments came close to meshing into a cohesive panorama. Whatever else it was, the Vegas program was more entertaining than any entertainment show on a network that night.

Maybe that week.

Andrew Heyward, the executive producer of "48 Hours," says next Tuesday's program will be "48 Hours on the Campaign Trail," keyed to the New Hampshire primaries that day. Live updates on results will be incorporated into the body of the show, which was taped Feb. 8 and 9.

Considering the fury caused by Rather's big head-butt with George Bush, it's hard to imagine the Bush people inviting "48 Hours" to join them for behind-the-scenes peeks. "Well before the incident," says Heyward, "we had asked all the major camps for special access, and Bush's was among many that turned us down."

Heyward claims not to be upset about the exile to "Cosby" time. "The people who program this network genuinely believe it's better for me," he says, because in the Tuesday slot both ABC and NBC had highly competitive shows, whereas on Thursdays only NBC does.

Of course, NBC's one show gets as big a rating as two normal shows do.

If ratings don't pick up for "48 Hours," the plug will be pulled at the end of the season, no doubt. The series has crash and bang galore, but noise is not music, and not news, either. "48 Hours" is all variations and no theme.