The electrode gap has widened with use so the required firing voltage exceeds what the coil can deliver.
This generic fault record is not vehicle-specific. Applicability and repair choice must be resolved from vehicle context and test results.
Worn spark plug
At a glance
Fault summary
The electrode gap has widened with use so the required firing voltage exceeds what the coil can deliver.
SeveritySeverity not yet verified Drive?Depends on the exact symptoms EvidenceSource notes available
- Affected system
- Engine / drivability
- Severity
- Severity not yet verified
- Urgency
- Urgency not yet verified
- Can I drive?
- Depends on the exact symptoms Drivability is governed by symptoms and the approved diagnostic safety layer, not by this generic failure-mode label alone.
- Repair/cost band
- Cost band not yet verified
- Vehicle applicability
- No structured vehicle applicability verified yet
- Evidence/confidence
- Source notes available See source & evidence notes below
Short answer
The electrode gap has widened with use so the required firing voltage exceeds what the coil can deliver.
Drive?Depends on the exact symptoms
Can I still drive with this?
Depends on the exact symptoms
Drivability is governed by symptoms and the approved diagnostic safety layer, not by this generic failure-mode label alone.
Common symptoms
- I can feel it stumbling or shuddering
- It hesitates when I accelerate
- It takes a long time to start when cold
- It is using more fuel than it used to
Likely causes
- Normal service wear
- Deferred maintenance
Diagnosis checks
Swap two ignition coils
Inspect the spark plugs
Check which cylinder is misfiring
Used-car buyer warning
Ask for documented diagnosis and repair evidence; do not infer this fault from one symptom or code.
Repair actions / cost band
Repair action and cost band are not yet verified.
Source & evidence notes
- CarFaultIQ diagnostic failure mode fm_spark_plug_worn, manifestation relationships and test effects. Safety review status: pending_human_review. No vehicle-specific prevalence is claimed.