This module covers a series of real-world diagnostic case studies using scope waveforms and scan data, with a focus on interpreting evidence correctly and avoiding common diagnostic pitfalls.

Cases include:

• Post-repair ignition analysis on a Cirrus, including residual energy oscillations and their modern limitations as a diagnostic indicator
• A 90 Subaru Legacy with cylinders 1 and 2 dead at idle only, where an IAC fault caused the ECU to cut injector pulse width — and why the trouble chart would have led you to replace a perfectly good ECU
• A Dodge Caravan 3.3 with two dead cylinders traced to a broken flywheel causing a shifted cam/crank relationship, and how to identify image overlay artifacts on a Fluke 97
• A MAF sensor contamination diagnosis on a Ford with lean codes under load but normal trims at idle, including how a fuzzy hot wire affects readings differently at idle vs. cruise
• A no-spark 89 Jeep Wrangler 4.2 diagnosed through primary coil current and voltage waveforms pointing to a failed ignition control module
• A 94 Camaro Optispark low-resolution signal failure captured with a PicoScope after a Fluke 97 proved inadequate for the task
• The well-known GM 3800 upper intake plenum coolant ingestion failure, including the risk of hydrolock damage and the danger of plastic intake manifolds during backfire events