Dodge Charger P0300: Random or Multiple Cylinder Misfire Detected

Dodge Charger P0300 Random Misfire Diagnosis

Quick Answer: What is P0300?

On a Dodge Charger, the P0300 code triggers when the PCM detects that multiple cylinders are failing to ignite. In the 5.7L Hemi V8, this is often due to worn-out spark plugs (16 total) or collapsed lifters. In the 3.6L V6, it is commonly caused by faulty ignition coils or carbon buildup on the valves.

Urgent for Hemi Owners: If your Charger has a rhythmic "ticking" sound that speeds up with the engine, you likely have a mechanical lifter failure. If the Check Engine Light is flashing, stop driving immediately to avoid destroying your catalytic converters and camshaft.

Common Symptoms

Engine Stumbling: The car jerks or hesitates during acceleration or when idling.
Rough Idle: Significant vibration felt through the steering wheel and seat.
Flashing Check Engine Light: Indicates a severe, active misfire.
Reduced Power: The Charger feels like it has lost its signature muscle.

Most Likely Causes

Worn Spark Plugs (45%): The Hemi engine requires 16 spark plugs; neglecting them past 100k miles is the #1 cause of P0300.
Failed Ignition Coils (30%): Coil-on-Plug failure is common as these engines run hot.
Collapsed Lifters (Hemi Tick): A mechanical failure in the 5.7L engines that prevents valves from opening.
Vacuum Leak: Cracked intake manifold gaskets or a leaking PCV hose.

Detailed Repair Cost Breakdown

Estimates for Dodge Charger (3.6L V6 and 5.7L V8) in the US market:

Component / Task	Aftermarket Part	OEM Mopar Part	Labor Time
Spark Plugs (Set of 16 for Hemi)	$120 - $180	$220 - $320	2.0 - 3.5 hrs
Ignition Coil (Each)	$45 - $70	$115 - $165	0.5 hr

How to Fix P0300 on a Dodge Charger

1. The 16-Plug Rule (Hemi V8)

If you own a 5.7L Hemi, you cannot just change 8 plugs. Each cylinder has two. If you are over 100,000 miles, replace all 16 with Genuine Mopar or NGK Iridium spark plugs. This is the most common fix for a random misfire on this engine. Using cheap plugs will almost certainly cause the light to return.

2. Test the Coils

If your scan tool shows a specific cylinder (like P0301), swap that coil with cylinder 2. If the code moves to P0302, the coil is dead. Dodge engines are sensitive to electrical resistance, so only use high-quality coils to ensure a smooth idle.

3. Inspect the Intake Manifold Gaskets

On both the V6 and V8 engines, the plastic intake manifolds can develop leaks at the gaskets. Spray a small amount of carb cleaner around the intake ports while idling. If the engine RPM jumps, you have found a vacuum leak. Replacing the $40 gaskets is a far cheaper fix than a full tune-up.