I have a 1997 Civic MT with 120k. There is a deep banging noise I hear at least once a day generally when accelerating in 2nd or 3rd gear. The duration of the noise may be 5 seconds. I experience no loss of power or gear slippage or any other effects, just this noise. I have been to 2 dealers who are unable to pinpoint the cause. I have been told it may be my clutch, but I have never experienced any gear slippage or clutch pedal oddities.