Drive it again and watch the tach, preferably in a higher gear. If you are fully in a gear, the engine speed cannot change that rapidly. If the tach needle jumps around when the engine misfires, I would be looking at the low voltage side of the ignition system (TFI module, wiring, dizzy). If the tack does not bounce when misfiring, then it's air/fuel related (MAF sensor, bad injector, etc.) or high voltage side of ignition (plugs, wires, coil).
Fast Frank Motorsports LLC
High performance solutions