Very energetically and successfully: Everyone knows I'm getting into your pants like gangbusters/ The rest of the year the economy will be going like gangbusters(1942+)
Energetically, forcefully, loudly. For example, This is a soft passage—the horns shouldn't come in like gangbusters. This expression alludes to a popular radio series entitled Gangbusters, which featured explosive sound effects, such as gunfire and sirens, at the beginning of each episode. [ ; late 1930s ]