Waveform Diagnosis
Primary Ignition — Cylinder 1 Anomaly
Signal Analysis
✗ Burn Time Collapsed40%
Cyl 1 burn oscillation is 0.8ms vs expected 2.1ms — signal exits tolerance band completely during burn phase
✓ Spark Voltage Normal20%
Initial spike reaches -285V (within ±15% envelope: -250 to -350V) — coil primary circuit is good
✓ Dwell Period Normal15%
3.2ms matches ECU command — signal stays within tolerance band throughout dwell
✗ Burn Amplitude Loss25%
Post-spark oscillation drops to ±5V (tolerance: ±12-18V) — deviation heatmap shows solid red through Cyl 1 burn
Interpretation
Coil produces adequate initial spark but combustion doesn't sustain. The deviation heatmap clearly shows Cyl 1's burn phase is the ONLY region outside tolerance — all other phases for all cylinders are within the green band. Pattern matches fouled/worn spark plug rather than coil failure.
Recommended Action
Inspect Cyl 1 spark plug. Check gap (spec: 0.044"). If fouled/worn, replace all 4 as a set. Re-capture waveform to confirm burn pattern normalizes.
Correlated DTCs
P0301 — Cyl 1 Misfire
P0171 — Lean B1