What Does Ford Code P0300 Mean?
- P0300 definition: Random, Multiple Misfire Detected
- Issue Severity: SEVERE – Stop driving immediately
- Repair Urgency: Fix this code immediately (same-day if possible) to avoid ignition failure, catalytic converter damage, and dangerous conditions
- Diagnosis: A multiple misfire can be caused by anything from faulty spark plugs to low engine compression. You can take your car into a shop, or save money by learning how to diagnose and fix your problem yourself with our P0300 guide.
- 3rd most common cause of a check engine light in Ford E-350 models.
Your vehicle moves when gasoline is burned and power is generated inside a chamber known as the cylinder. Most engines have a 4, 6, or 8-cylinder engine, where more cylinders typically mean more power. Power is generated by pistons that move up and down while fuel is ignited at very specific times. A misfire typically occurs when the timing of this ignition is off. P0300 indicates that two or more cylinders are experiencing misfires.
Ford P0300 Causes
Misfires can be caused by many reasons from a faulty ignition system, fuel system, or internal engine failure. The most common reason for this to happen is faulty or worn-out spark plug coil packs, especially if it’s been a while since you had a tune-up.
- Faulty or worn spark plugs and/or spark plug wires
- Ignition issues, including failing or damaged ignition coils
- Distributor failure
- Faulty fuel injector
- Vacuum leak
- Low fuel pressure
- Camshaft and/or crankshaft sensor defective
- Engine timing off
- Leaking head gasket
- Low engine compression
- Poor quality fuel that is old or contaminated
>>> RELATED: How to replace spark plugs
>>> RELATED: Average cost to replace spark plugs
Ford P0300 symptoms
- Check Engine Light is on
- Check Engine Light flashing
- Engine runs rough and shaking
- Lack of power from the engine
- Fuel smell from the exhaust
- Hesitations/Jerking when accelerating
How do I fix Ford code P0300?
With a misfire fault, the first step is to get it diagnosed to figure out what is causing the engine to misfire. We’ve created this 100% free step-by-step guide to show you how to diagnose and fix your P0300 code.
>>Click here to download your FREE P0300 Fix-It Guide!
If your vehicle is misfiring and you’re not comfortable diagnosing this issue at home, we recommend finding a RepairPal certified shop nearby to pinpoint the problem and give an accurate estimate for repairs.
These shops can not only help you figure out what’s going wrong before you waste time and money on the wrong parts, but they also offer a minimum 12-month, 12,000-mile warranty and stand behind all their estimates with guaranteed fair pricing.
How much does it cost to fix Ford P0300?
For error code P0300, one or more of the below repairs may be needed to solve the underlying issue. For each possible repair, the estimated cost of repair includes the cost of the relevant parts and the cost of labor required to make the repair. These prices are based on national averages. Your cost may differ depending on your location. Click on the links to learn more about each repair.
- Spark plugs cost: $66-$250 (depending on if you take it to the shop or do it yourself)
- Ignition Coils: $230-$640 (some cars require Intake manifold removal)
- Spark plug wires: $180-$240
- Fuel injectors: $1500-$1900
- Vacuum leak: $100-$200
- Fuel pump: $1300-$1700
- Fuel pressure regulator: $200-$400
Can I fix Ford code P0300 myself?
Ford code P0300 is considered an intermediate level diagnosis and repair for most DIYers. Download our free guide and follow the steps to diagnose and fix this fault code or schedule repairs so you can get back on the road.
Ford code P0300 Diagnosis Steps
Tools Needed to Diagnose:
- Tools You May Already Have:
- Tools You May Need (FIXD’s Top Picks From Amazon):
- FIXD
- Digital multimeter
- 5/8in. Spark Plug Socket
- Ratchet, sockets, and extensions
- Fuel pressure gauge
- Compression tester
- Leakdown tester
- Spark plugs
- Spark plug wires
Step 1: Use FIXD to scan your Ford to verify P0300 is the only code present.
If other codes are present, they must be addressed first.
Step 2: Check for loose connectors at the ignition coils or for damaged wiring.
Look for loose engine ground wires as well. These can cause random misfire conditions. Tighten or connect where necessary.
Step 3: Check the condition of your spark plugs and spark plug wires.
Worn and old spark plug wires are common causes of random misfires. Replace spark plugs and wires if needed and recheck for misfires.
Step 4: If you have determined that your ignition system is operating correctly.
There may be a problem within your fuel system that is causing the random misfires. The following should be checked to ensure the engine is getting the proper amount of fuel:
- Check fuel pressure. Low fuel pressure can cause intermittent misfires on multiple cylinders. When the pressure is below the specification, the engine does not receive the proper amount of fuel and will start to lean misfire. The fuel pump or fuel pressure regulator could be the source of the low fuel pressure.
- Check that the fuel injectors are functioning properly and activating. Random misfires can be a sign of faulty or clogged fuel injectors that need to be replaced. Also check that the fuel injector wiring is not damaged and is connected properly.
Step 5: If the ignition system and fuel system checks out you may want to perform an engine compression test and leakdown test to see if there are any mechanical problems causing your misfire.
Some common mechanical problems that cause misfire can be:
- Broken valve spring
- Broken piston ring
- Worn valve guides
- Burned valve
- Timing chain or belt skipped tooth and engine is off time.
Still need help fixing Ford code P0300?
If you’ve followed the steps above and are still experiencing misfires or check engine code P0300, please contact the FIXD Mechanic Hotline if you’re a FIXD Premium subscriber or find a RepairPal certified shop near you to get the right repairs at a fair price.
- Get Your Code Fixed Fast
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Fixed It But The Check Engine Light Is Still On?
Check engine light sometimes need to be reset manually, check out our article:
How to Reset Your Check Engine Light | 4 Ways To Clear It (With or Without a Scanner)
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