P0300 Random/Multiple Cylinder Misfire — Causes & Fix

What Does P0300 Mean?

P0300 is a generic OBD-II code indicating the Engine Control Unit (ECU) has detected misfires across more than one cylinder, but not consistently in any single cylinder. Unlike P0201–P0204 (which point to a specific cylinder), P0300 suggests a system-wide issue — typically fuel delivery, injection quality, or compression problems affecting the entire engine.

P0300 at a Glance

• What it means: The ECU has detected misfires occurring randomly across multiple cylinders.
• Most common cause: Worn or failing injectors, fuel supply issues, or low compression.
• Severity: Serious — affects all cylinders, can damage the DPF and catalytic converter rapidly.
• Can you drive?: Short distances only. Multiple misfires accelerate DPF damage.
• Typical repair cost: £100–£1,400 depending on how many injectors need replacing.