DIY - How to Diagnose Bad Spark Plugs & Ignition Coils!

Ignition issues getting you down? A bad spark plug or bad ignition coil could be the culprit! Understanding the symptoms of bad spark plugs and ignition coils and diagnosing these problems are essential for smooth engine operation. Today, we're diving deep into the heart of your vehicle's ignition system, unpacking the mystery behind spark plugs and ignition coils, and providing hands-on advice on spotting and resolving common problems. Join Jake as he equips you with the skills and insights needed to ensure optimal spark plug and ignition coil performance. Whether you're a seasoned mechanic or just an enthusiastic car owner, we’ve got you covered!

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8020 Media owns and operates a portfolio of content websites and eCommerce stores in the Automotive industry. We provide over a million monthly readers with high-quality automotive content, focused predominantly on technical and performance modification guides.
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00:14 – How Spark Plugs & Ignition Coils Work
00:30 – Visual of How Spark Plugs & Ignition Coils Work
01:08 – Maintenance Intervals for Spark Plugs & Ignition Coils
02:04 – Symptoms of Bad Spark Plus & Bad Ignition Coils
03:02 – More Maintenance Tips for Bad Spark Plugs & Ignition Coils
03:32 – How to Diagnose Bad Spark Plugs & Ignition Coils
04:30 – What Engine Cylinder is Having an Engine Misfire?
05:13 – DIY Diagnosing Bad Ignition Coils & Spark Plugs
07:11 – How to Diagnose Bad Spark Plugs & Ignition Coils Outro

[lowerclassbrats]

I took my Hyundai Accent to the dealer (1st mistake) for a diagnostic for engine surging. They diagnosed it as a bad ignition coil. They quoted me a repair cost of $1200.00usd. I did 5 min of research (watched you tube vid). I bought the parts for $230.00 and fixed it myself in 15 minutes.

I changed all 4 spark plugs and all 4 ignition coils so I didn't have to play the process of elimination game. Do yourself a favor and do a modicum of research prior to paying someone to do something you could do without breaking a sweat. The price I was quoted should be classified as a crime.

Pay for the diagnostic at a place like Midas where it's cheaper and fix it yourself, depending on the degree of difficulty.

[ashrafothman]

Short but very precise explanation. It clarify my confusion between faulty spark plug and coil. Thank you very much for sharing

[Kate.Nkechi.O]

Thank you! The mechanic really was trying to tell me to replace my ignition coils when all I wanted was my spark plugs replaced.

[blackstonecap]

Thanks for the clear, detailed explanations.
On my 09 Silverado I only get a PO 300 code and not a 301 or 302, etc.
Sounds like I am going to do process of elimination.
Thanks to your video, I have an idea how to proceed

[yourecancelledfromsociety]

Luckily I have a 2013 frs, spark plug and coil packs are ultra easy to access

[kyleclementz]

Thanks for your help! Great explanation

[hmfem]

Great job in explaining. My Chrysler Town & Country is currently at the dealership to replace its spark plugs & I was advised by the technician to replace the ignition coils as well since he was already there. My town & country has 98, 586 miles & is ready for the100, 000 miles checkup.

[happymood]

Thank you sir very knowledgeable very easy

[happycat]

To diagnose bad plugs just remove the spark plug and look for a plug with light brown colouring. Bad coils will causing stalling, engine hesitation and the poor overall engine performance. I have NGK Irridium plugs in my 2002 Rav4 and the engine still runs like it is new. The Toyota OEM ignition coils lasted for 275, 000 km before they finally gave out. DIY replacement cost was about $220 Canadian for 4 new coils, a new EGR valve, a new PCV valve, a new MAF sensor, and a battery. Not bad for a car that I rarely maintain....

[HeydaCarreras]

What is that metalic silver cover you have on wires and hoses?

thnx for these info. My fx35 2009 lately feels like it is not smoothly shifting from 1st to 2nd gears. I feel a slight miss, if i accelerate slowly when moving from a stop, but if I move rapidly this slight hesitation is not felt. Can you say what you think may be the cause. This suv idles steadily, and drives ok, but I know it is just not right, something is causing this new feel in the drive.

[JuanTorres-op]

Do I have to disconnect my battery before taking out the ignition coils?

[heidia.]

Do these faulty parts result in a Toyota Fielder not starting?

[konstantin-big]

Before i change=carry over the ignition coils
I unscrew the sparkplug that i have error code f.ex. p0301 and test if that is ok, if that's not ok, i replace that sparkplug

[JoeBuckelk]

What if the code only reads p0300 and doesn't say a specific cylinder? I know it may be multiple but how do I know which ones?

[JoeBuckelk]

What if the code only reads p0300 and doesn't say a specific cylinder? I know it may be multiple but how do I know which ones? It's has to be a ignition coil because I changed the plugs

[dennistirado]

Thanks for the information. I have a problem I am hoping you can shed some light on. I had engine misfire and replaced all. the coils and spark plugs. The misfire went away. Also have a new fuel filter. Six months later, I am experiencing a random misfire. Sometimes the car runs perfectly, and all of the sudden it misfires for a few seconds. Sometimes the "Service engine light soon" flashes on and off during the misfire. Then it goes back to running ok. I have poured motor treatment liquids to see if cleaned injectors and the such. Once it misfires, I can detect a P0300 code and troubleshooting this has been difficult. I do not get more specific codes. 2003 GMC Envoy XL 4.2L 6 Cyl. Any thoughts?

[AnthonyPR-jxsb]

I would like to say thank you for taking the time and effort to help other people
and also would like to know if you can advice me with my Honda Accord 2006 I have a check engine light and I already replace the catalytic converter (after market) also the o2 sensor twice and I don't know what else to do

[HighHeelsAndPonytails]

Is there a way to tell if your new ignition coils are faulty? Spark plugs were all changed last year and only 1 ignition coil. Check engine light, recently came back on mechanic said it was the same issue. All coils have been replaced as of today however the issue yet persists. Any tips guys?

[AlwaysDiagnoseVehicleFirst]

I have a 2003 Dodge Caravan Se V6 3.3 and it has a coil pack, in this video your swapping individual coil on plugs from cylinder 1 to cylinder 2, how do i apply the same swapping diagnostic test on the coil pack, can you help me with that, please?