System: Powertrain (P-Code)
SAE Standard (Generic)
Family: Misfire Random Multiple
Code P0300: Random/Multiple Cylinder Misfire Detected
Diagnostic & Technical Explanation
Code P0300 (Random/Multiple Cylinder Misfire Detected) sets when the ECM's crankshaft-acceleration misfire monitor counts combustion events across multiple cylinders (or an undifferentiated pattern) beyond the calibrated threshold, including variants triggered by a low fuel level, a cold-start window, or a commanded fuel cutoff. Because no single cylinder is isolated, the cause is almost always something that affects the whole engine at once: a vacuum leak, worn spark plugs across the set, a weak fuel pump/low fuel level, or a base ignition timing/reluctor fault.
First-listed procedure
Rank #1
Replace spark plugs and inspect ignition coils as a set
Easy DIY
This is the first procedure in the authored
consideration order, not a measured cause likelihood. Execute it only when its prerequisites
and diagnostic findings support it. Its cost and labor estimates (where known), the step-by-step procedure and the
remaining 3 procedure(s) are in the licensed dataset. Ordering context.
Full family: Misfire Random Multiple
What this page does not show
This page publishes the fault mechanism and the code index. The licensed dataset adds, for
every one of the 15,886 codes, the full authored repair set (56,729 procedures in total)
with the fields deliberately withheld here:
- Procedures 2..n after the first-listed procedure
- Aftermarket parts cost ranges in USD (
est_parts_cost_min/max_usd)
- Professional labor-hour estimates (
est_labor_hours)
- Step-by-step diagnostic and repair instructions
- Replacement-part mappings and catalog lookups
- 6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)