Skip the auto shop - Our mechanics make house calls

Q: Check engine light P0302

asked by on

My check engine light came on which produced a P0302 error code. I swapped out the engine coils in cylinder 2 & 4. I cleared the codes and started the car and ran it for a little bit. Now it is throwing P0304. So this tells me the engine coil is bad and should be replaced. If I have to replace one (I have 110,000 miles on the car), should I go ahead and replace all of them or will I be safe just replacing the 1? Also, what about spark plugs in these cars? Should they be replaced or are they good for the lifetime of the car?

Hello there, thanks for your question. I’d be happy to help. It does sound like a bad ignition coil is the cause of this P0302 trouble code. This is not uncommon since your car has over 100,000 miles. If it is just one coil causing the issue, then you should simply replace that one coil. Over time, the other coils will fail but that can be over a period of weeks, months, or even years. In my personal opinion, it is not worth changing them all if they are not bad. As for the spark plugs, they should be replaced at 100,000 miles. By not replacing them, the coils will work even harder which will cause them to fail prematurely.

If you would like help inspecting this or replacing the ignition coil, consider having an expert automotive technician from YourMechanic come to your home or office to make the necessary repairs for you.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Gas pedal pressed to floor before car accelerates

Hello, we will be happy to assist you. I would suggest that you have a technician use a capable scan tool to perform a function test on the vehicle. Doing so will test most of the sensors on the vehicle...

Q: P0302 (rear rotor misfire) and CEL not going away

Hey there. Your engine is misfiring but not until your engine is at high RPMs. The cause can be that you are not getting enough fuel or spark to the cylinder. You should have the engine cleaned of carbon, clean...

Q: My car cranks over, but won't start, or even sound like it might.

Hello, It sounds like you may have a bad fuel pressure regulator or potentially a leaking or faulty fuel injector. I would suggest having an expert from YourMechanic come to your location to run a fuel pressure test to determine...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...