Richard Chang suggested a useful addition to the FAQ: a reference guide to various Bosch sensor and other outputs based on digital storage oscilloscope images captured from actual known-good or known-faulty engines. As our cars age, we will find waveform analysis to be a more useful technique. Picotech has a very few images for 940 cars; an example is below. If anyone has a DSO and is willing to capture images along with the operating conditions (idle, full throttle, etc.) and send them along, I will collate them into a waveform image library and place it in the FAQ for use by all.