The M1 won the dubious distinction Tuesday of being named the most unreliable bus line in the city.A "golden question mark" was bestowed on the East Side bus route at the fifth annual Pokey Awards, organized by two transit advocacy groups, the Straphangers Campaign and Transportation Alternatives, to call attention to poor bus service.The groups' "golden snail" award -- for the slowest bus -- went this year to the 14th Street crosstown bus, the M14A.It was the first time the groups named a most unreliable bus. The M1, which runs from Harlem to the East Village, was chosen because of long waiting times in between buses, the groups said.On weekdays the bus, which goes up Madison and down Fifth and Park Avenues, should stop every eight minutes.Instead, it travels off-schedule with big gaps between buses -- 27.6 percent of the time, according the Straphangers Campaign, which calculated the results using Metropolitan Transit Authority statistics.The M3 was the second-most unreliable bus with a 25 percent rate, and the B15 came in third at 24.7 percent.Some M1 riders, however, were surprised that the M1 was singled out for being unreliable."No, it comes very frequently," said Nancy Mathis, an oncology nurse who rides it daily between 23rd and 110th streets.In the slow-poke category, the M14A averaged 3.9 miles per hour and beat out, or rather, lagged behind last year