P0302 – Meaning, Causes, Symptoms, & Fixes

Code P0302 Definition

Cylinder 2 misfire detected.

  • Commonly associated with codes: P0300

What Does P0302 Mean?

P0302 indicates that cylinder number 2 is experiencing misfires. A misfire occurs when an insufficient amount of fuel is burning in a cylinder. The efficient burning of fuel is essential to engine operation as the combustion of fuel is what provides the energy to power the engine. A misfire from one or more cylinders can be caused by many reasons from a faulty ignition system, fuel system, or internal engine failure. When P0302 occurs, it should be fixed immediately as long term driving with engine misfires could cause consequential damage to your engine.  Many times, P0302 occurs when there are worn out spark plugs, spark plug wires, or a faulty ignition coil.

What Are the Symptoms of Code P0302?

  • 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

What Is the Cause of Code P0302?

 (* = Most Common)

  • Faulty or worn spark plugs *
  • Faulty spark plug wires or coils *
  • Distributor failure *
  • Faulty fuel injector 
  • Vacuum leak
  • Low fuel pressure
  • Camshaft sensor defective
  • Crankshaft sensor defective
  • Engine timing off
  • Leaking head gasket
  • Low engine compression
  • Poor quality fuel

How Serious is Code P0302? – Severe   

 

P0302 should be repaired immediately. Ignoring this error could result in ignition failure, catalytic converter damage, and unsafe/dangerous conditions while operating the vehicle.

Code P0302 Common Diagnosis Mistakes

Loose fitting electrical connectors and broken or disconnected vacuum hoses are often overlooked.

Code P0302 Diagnosis Steps:

Tools Needed to Diagnose:

How To Diagnose P0302:

Difficulty of Diagnosis and Repair – 2 out of 5

  1. Use FIXD to scan your vehicle to verify P0302 is the only code present. If other codes are present, they must be addressed first.
  2. Check for loose connectors at the ignition coils or for damaged wiring (specifically cylinder 2). Look for loose engine ground wires as well. These can cause random misfire conditions. Tighten or connect where necessary.
  3. Check the condition of your spark plugs and spark plug wires. If your vehicle is equipped with individual coil packs instead of spark plug wires, start by removing the cylinder 2 coil and swapping it with the cylinder number 4 coil. If the misfire moved to cylinder number 4 (P0304), then you have determined that the coil pack is faulty and needs replacement. You can do the same test with the spark plug, i.e., move cylinder 2 plugs to say cylinder 3 and if the misfire is now P0303 then the plugs are at fault. Replace spark plugs and spark plug wires/ignition coil packs if needed and recheck for misfires. (How to identify a fouled spark plug, How to test spark plug wires, How to gap spark plugs, How to replace spark plugs, How to swap ignition coils).
  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. (How to check 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. (How to check fuel injectors by ear, How to check fuel injectors with a digital multimeter)
  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:
    • Leaking head gasket
    • Broken valve spring
    • Broken piston ring
    • Worn valve guides
    • Burned valve
    • Timing chain or belt skipped tooth and engine is off time.

Estimated Cost of Repair:

For error code P0302, 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. 

  • Spark plugs $40-$640 (some cars require Intake manifold removal)
  • 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

Was this post helpful?

Comments 17

Ric Dale

July 21, 2018

You missed water in fuel/bad fuel.
All cylinders were tagged as misfiring and stopped when the tank was refilled.
I will be using Sea Foam on my next fill up.
By the way. I could not clear these codes with FIXD.

FIXD Marketing

July 25, 2018

Hi Ric,

Thank you for the tip! You will need the FIXD sensor and the mobile phone application in order to clear the Check Engine Light in your vehicle. If the problem with your vehicle persists, the Check Engine Light could keep setting codes.

Thank you,
The FIXD Team

Hans de Jongh

September 8, 2019

I am also unable to clear the code. The app just tells me it’s communicating and then redisplays the code. I believe I had a temporary problem. Engine ran rough for a few minutes but has been smooth ever since. I want to reset the code to see if the problem comes back.

Tim

December 1, 2018

Hi I have a 2000 Lincoln town car I recently had to replace the intake and since the my car has not ran correctly it keeps throwing p0300, p0301, p0302, p1450 codes and I have replaced fuel injectors, spark plugs and nothing is working…. could the purge valve be the reason these codes keep coming back

Cheryl L March

July 15, 2019

This was very informative! Now’s I can do some things without asking my son. I love my independence.

MelT

January 3, 2019

I swapped plug wires, coil packs and checked the plugs, wiring etc. I recently replaced vacuum hoses this past summer but they were all connected. I realized that I had put gas in at a station I rarely use and had driven just enough to have the check engine light come on. I used iso heat first, to absorb the water. Then I drained the gas tank and added 5 gallons of fresh gas with seafoam added. My car started up and all symptoms gone. Cleared the code. Fixd was definitely handy. The last symptom is bad fuel.

Melly

January 17, 2019

Try seafoam motor treatment fixed my 302 misfire

Derick

April 27, 2019

Out of curiosity, what kind of car do you have? I have a charger that will not shake this code off, changed everything but still there

Julie

October 10, 2019

I have a 2014 dodge charger and the 302 code keeps reappearing also. Plugs and wires have been changed. This code only started happening since they did recalls this year.

T

May 24, 2019

Was your car vibrating and slighly jerking , seeming like its about to backfire before the seafoam?

Peter Whitney

June 3, 2019

Rick. I have a Pontiac Sunfire and the #3 spark is misfiring. I have changed all the spark plugs and the boots, but it continue to say misfire #3. Is there something that I can do to fix this problem?

Bob

June 22, 2019

The problem with this code on my 2006 Pontiac Vibe was a bad ignition coil.
I replaced the coil for $90 . The code is gone and the Vibe runs smooth again. Thanks for the help.

Cheryl L March

July 15, 2019

This was very informative! Now’s i can do sooner things without asking my son. I love my independence.

Liyah

July 26, 2019

I have a dodge 2014 charger and my ABS light and check engine light are both on. They thought it was because of the spark plugs and etc (cylinder misfire), but they called back and said that it has something to do with my head gasket. The maintenance will be around $2,000 including labor. Is there any other possible things that could be wrong?

Betty

August 15, 2019

changed all spark plugs and coil engine light still comes on with code p0302

Betty

August 15, 2019

changed all spark plugs and coil engine light come back on with code P0302

Dave Edwards

October 2, 2019

I have a 2007 Chrysler 300 touring. My engine light keeps coming on, had it into mechanics and cannot resolve a P0300 random cylinder misfire. I was looking to purchasing an older truck and the seller informed me that “I should check my tail lights – TRUST ME”. Well it does turn out that the Brake Lights do not work. All turn signals, hazard warning lights, and parking lights do work and I suspect that my brake switch is bad. I have checked for voltages at the reverse light (it’s there w/ approx. 11.7 vdc, parking light voltage is there w/ approx. 11.8vdc) but no voltages when brake pedal is depressed. Lights are good and no shorts but only an open where supposed to be. Anyone know ANY relationship with brake lights and engine/P0300 code on 2007 Chrysler 300 touring. Has about 181k miles and original owners of it.

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