Abstract: A preferred data display apparatus (10) includes an engine analyzer (14), computer (16) and a display device (18). The computer (16) receives waveform data representative of a waveform characteristic of engine operation from the analyzer (14) and produces a waveform display on the device (18) representative of the waveform. The waveform display includes segments (30a, 30b, 30c) displayed in different colors and in a three-dimensional representation. In preferred forms, a mouse (20) is used to snap a cursor (32) along the waveform and display includes amplitude and time data representative of the position coordinates of the cursor (32) and thereby representative of the cursor's position on the waveform. The preferred apparatus is operable to display waveforms derived from different sources.