When it comes to crunch time, the Dolphins get crunched.

The Dolphins have relinquished 49 percent of the points scored against them this season in the last 25 percent of their games.

The Dolphins are the worst team in the NFL in the fourth quarter.

What does such unraveling say about the Dolphins' fortitude, fitness, concentration and confidence? More important, what does it say about the Dolphins' talent?

Coach Tony Sparano is trying to figure it out, as his team's pattern of collapse continued Sunday in Orchard Park, N.Y., a place where Buffalo Bills fans probably can go ahead and erect another tombstone for Miami's playoff hopes.

The Dolphins were outscored 24-0 in the fourth quarter, blowing a 14-7 lead to lose 31-14. They should have won, of course, especially against a rookie interim coach, a fill-in quarterback and a faltering division rival decimated by injuries. Especially since the Dolphins, now 5-6, are chasing a playoff berth.

Were chasing a playoff berth?

The result was ``not acceptable,'' Sparano said Monday. He took the blame for not having his team prepared. He bore the brunt of criticism for some very funky calls, such as Ricky Williams' first pass attempt in nine years, on first down from the 3-yard line, which was intercepted.

But his players know that when a team is embarrassed 24-0 in the fourth quarter, there is an abundance of blame to go around.

``We didn't match their intensity,'' Greg Camarillo said in a painfully blunt assessment. ``They played with a lot of energy at the end of the game and we didn't.

``It was the type of situation where if you jump out to a lead maybe they back off as a losing team. But give them hope and they'll play hard if not harder. They played hard, enthusiastic football for 60 minutes and we let up at the end.''

It's a maddening habit of the Dolphins, who have given up 134 points in the fourth quarter while scoring 74. They have been outscored in the fourth quarter in seven of their 11 games, and have outscored their opponent in the fourth only twice.

Good teams rise to the occasion. Miami just isn't that good. Not yet.

And if the team lacks heart when it needs it most, it doesn't deserve to go to the playoffs.

Reggie Torbor does not believe the Dolphins gave up in the closing minutes at Buffalo. But he admits it sure looked bad as the Bills scored on a field goal and two touchdowns.

``You don't want to look like you laid down, whether you play in the NFL or work at McDonald's,'' he said. ``Perception is all that matters.''

Killer instinct was another missing trait. As Justin Smiley said: ``When you have a chance to put your foot on somebody, you have to do it.''

Sparano tried to break it down clinically into ``momentum plays'' -- mistakes that shift opportunity to the opponent. He said the Dolphins yielded 20 of those from the last drive of the third quarter through the fourth. He'd like to limit the number to seven or eight. He mentioned a missed tackle that allowed enough extra yards to set up a 56-yard field goal. A mediocre kickoff return and false-start penalty by Ted Ginn Jr. that put Miami on its 16 with 3:30 to go. Pressure on quarterback Chad Henne that led to an interception, and on the next play Terrell Owens caught a 51-yard touchdown pass.

For the Dolphins, the devil is in the details.

They might lack the dazzling superstars to overcome mistakes but they do have the brains to avoid making so many in the first place.

What's happening in the fourth quarter is that the Dolphins' deficiencies are getting exposed. For example, everyone knows they do not have a quick-strike offense. They don't have a Terrell Owens. They need a hearty six minutes to chug down the field and score.

In the fourth quarter, the Dolphins' linchpins crack under the weight of carrying an incomplete team.

``It's no big secret that we can't finish,'' Torbor said. ``It's not like we're in denial. We're knowing, but not doing.''

The Dolphins are what they are -- a work in progress. They could get hot in their final five games. Stranger things have happened in the NFL. But only if they find a way to reverse their fourth quarter fortunes can they reverse the trajectory of this season.