JB3 - Verify Scope Pattern 2

Spark Plug Firing Voltage Pattern:

- Is the average value of spark plug firing voltage greater than 20 KV with evenness of spark plug voltage 8 KV or less?

YES -- Problems affecting all cylinders: Wide spark plug gaps all cylinders (usually from worn electrodes due to high mileage). CHECK ignition coil wires for proper installation in coil. MEASURE resistance of ignition wires. REPLACE if greater than 7000 ohms per foot.

NO -- Go to JB4. JB4 - Verify Scope Pattern 3