NEW YORK — Thousands of New York City taxi drivers overcharged passengers by more than $8.3 million over the past two years by setting their meters at a rate that was supposed to be used for trips to the suburbs, the Taxi and Limousine Commission said Friday. At least 1.8 million trips were wrongly charged at the suburban rate, which is double the rate within city limits, the commission said. The city has about 48,300 licensed cabbies, and data shows that 35,558 have illegally charged a rider at least once, the city said.