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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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

[@ashrafothman5227]

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

[@kyleclementz2462]

Thanks for your help! Great explanation

[@8020Media]

Kyle - Thanks for the feedback! We hope it helps.

[@TheBrownFamilyWorkshop]

very helpful thank you.

[@8020Media]

Brown - Thanks for the feedback! We hope it was helpful.

[@lowerclassbrats77]

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.

[@8020Media]

L - That's our exact goal, to assist anyone, regardless of automotive skill level, to be able to DIY issues. Thanks for sharing your experience!

[@yebogogo64]

Very clear explanation

[@8020Media]

Yebo - Thanks for the feedback!

[@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

[@8020Media]

L - Thanks for the feedback. We actually have a specific video done for those codes: kzbin.info/www/bejne/nGLQgmieeZZgrKs

[@simobonev4511]

Very useful

[@8020Media]

S - Thanks for the feedback. We hope it was helpful!

[@titop6152]

Thanks 🙏 😊

[@8020Media]

T - Thanks for the feedback!

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.

[@8020Media]

F - Do you have any engine codes?

[@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

[@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?

[@AF1MIDS]

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?

[@8020Media]

I - Yes, this is on a BMW. You might want to opt for a multimeter instead.

[@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

[@8020Media]

K - Pretty much, yes.

[@user-lt7gd2fu3d]

Hello :) I have a Honda Civic gx 2008 natural gas vehicle. It runa fine drivinh it for a bit . Then, out of nowhere, it starts slowing down even when i have my foot fully stepped on the gas. It doesn't accelerate.

[@8020Media]

E - Do you have any engine codes or engine lights?

[@richardsimms251]

Great

[@8020Media]

Richard - Thanks for the feedback! We hope it helps.

[@FOREVERHEREIGNS333]

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?

[@8020Media]

S - You may need to drive it for a little while for the codes to clear. Keep us updated on this.

[@konstantin-big]

Maybe you have another error code When you replace the ignition coil, the engine was running good Did you read the error codes???

[@AnthonyPR-jx1sb]

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

[@8020Media]

Anthony - Thanks for the feedback. Do you have a code reader?

[@AnthonyPR-jx1sb]

yes P0139

[@8020Media]

Anthony - Since you've already replaced the cat and O2 sensor, have you taken it to a shop? Only things we can think of are exhaust leaks somewhere, lean or rich running conditions, or PCM issues.

[@AnthonyPR-jx1sb]

I did took it to a shop and there is not exhaust leak ether, someone I know told it could be because the after market cat. is not big enough and this cost some kind of miss presure

[@8020Media]

Anthony - Certainly a possibility.

[@laineorlow1975]

On my 2002 Ford taurus 0:09 My car is hesitating and chugging and it misfired and checked the spark plugs. Too was not working and got new coil and the two same spark plugs still not working with new coil. Why are they not working?

[@8020Media]

Laine - Have you checked for any engine codes? This can assist in your diagnosing.

[@laineorlow1975]

@8020Media yes it wouldn't work on my car. They Scan it 2 or 3 times, and it wouldn't read it.

[@8020Media]

So you've taken it to a repair shop?

[@happycat0411]

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....

[@8020Media]

B - Thanks for sharing your experience.

[@dennistirado4619]

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?

[@8020Media]

Dennis - We think a video we made a little while back might be helpful: kzbin.info/www/bejne/nGLQgmieeZZgrKs

[@dennistirado4619]

Thanks, I watched the video. The frustrating thing is that I am only getting P0300. Most of time, the car purrs like a kitten, and when it sporadicly misfires, the "Service Engine Soon" light flashes on and off while the engine is misfiring. When the misfire stops, the light turns off. The check engine light never come or stays on. No other codes. I bought some coils and spark plugs from Amazon in April 2023.for $119 (six coils and six spark plugs). I did some tests (running the car and unplugging the coils one at a time) and all 6 seemed to be working ok. Later today, I did get a code P0302 and I replaced that one spark plug from Autozone - the p0302 code went away but still get misfires. I am leaning to think that the spark plugs that came in the Amazon set are not good quality and am thinking of replacing the remaining 5 spark plugs. The spark plugs read "Iridium ILT5RA 13G" but don't have a brand or code to identify anything else. IN my Amazon order it says Manufacturer LCWRGS? The air filter is clean, I have a new Fuel filter. After I change the spark plugs, I will proceed to a professional mechanic for compression and fuel test. Thanks again. (I am in the Temecula CA area).

[@8020Media]

Dennis. Sorry to hear about your frustrations. What vehicle do you have? Keep us updated!

[@dennistirado4619]

This morning, I tried two tips I saw on KZbin. One- when you clean your throttle, you have to reset the ECM in the throttle by switching the car on to the ON position and depressing the accelerator for 15 to 10 secs. I did that twice. The Second tip - since I had added an injector cleaner... was to put the car in first gear and accelerate to drive up the RPMs. I did that and it felt like if something got unclogged and the engine started revving better. I did a longer test drive and the misfire seems to have gone away. Also, I reran diagnostics and the P0300 is gone. Maybe I dodged a bullet. Thanks.@@8020Media

[@8020Media]

Dennis - Nice! Glad to hear this has been resolved. Also, thanks for sharing your experience! This will certainly help future viewers.

[@muhammadasadullah4269]

My car needs more acceleration, its fuel consumption is 7 km/litre. Its suzuki jimny automatic transmission 1.3. Can it be solved

[@8020Media]

M - How old is the car and how many miles?

[@devineleven514]

Lol my obd2 port is dead and i just changed all 4 coil packs and plugs. Damn thing started up running horrible. No power to even move forward. Backfires on high idle after rev to 3k. Im sure its the ignition coil connectors. Good ole 1.8t VW. Just bought a whole new harness to splice into. Wish me luck. Gib me some info on ohm meter test

[@devineleven514]

My turbo isn't connected via vacuum line to N75 Lmao but i hooked it back up. Bad mistake.

[@8020Media]

D - Did this fix it?

[@devineleven514]

​@@8020MediaI'll keep you posted

[@IsThatHuncho]

I had all these problems, but recently it got worse. I let my younger brother go to get food in my 2012 chrysler 200 2.4L. About 15 minutes into the drive he calls me worrying, saying the car started shaking. Misfires, hard starts, lack of engine power, and bad mpg were my symptoms, but not the pretty heavy shaking when idling or driving, which occurred yesterday. Any reasons that may have started happening? Oddly, the only engine codes i got were only on the catalytic converter, and catalytic converter gasket. So i’m not sure where to go from there and don’t have the money for a repair shop. :/

[@8020Media]

Huncho - Were those the only engine codes you got? Seems odd with everything going on. Sounds like it could be many things.

[@IsThatHuncho]

@@8020Media Yes oddly enough those are the only codes i got when i scanned my system. That’s why I’m so confused and not sure where to go from there.. Should i still try changing my coils and spark plugs still? Or should i just save up money for a shop? I have a eery feeling my transmission is going out but i’m hoping it’s not the case. It does have 140k so it wouldn’t be the least bit surprising if its my trans.

[@8020Media]

Huncho - Would hate for you to replace those components and it not fix the issue. So probably best to go to a trusted shop to get diagnosed, then go from there.

[@IsThatHuncho]

@@8020Media Reasonable, thanks for your time man.

[@8020Media]

Keep us updated!

[@hmfem3656]

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.

[@8020Media]

H - Thanks for the feedback! Always a great idea to replace both components at the same time.

[@GabbyA-vf1uv]

Even though it's not a Saturn. I found out something to look for I found that piece in a tool bucket. Have a mechanic who does a horrible job. Frustrated with him. His my husband and completely took my my coil and spark plugs and fuses. Now my car won't start.

[@8020Media]

G - So sorry to hear.. Keep us updated on this.

[@SB-wz1jj]

Is the ignition coil and spark plug wire are the same ???

[@8020Media]

Spark plug wire connects the spark plug to either the ignition coil or the distributor (depends what type of ignition system you have). So no they are not the same...you should replace the wires when you replace the spark plugs, though. They could be causing some issues, if not then you need to check if you have coils or a distributor and check that.

[@SB-wz1jj]

Thank you so much for the fast response and the good info cheers buddy

[@8020Media]

SB - Keep us updated.

[@ronniemcelroy9155]

Perfect but I'm not fire to my Coil . New plugs new coil still no fire

[@8020Media]

Then you probably have a fueling issue

[@tyronethomas820]

How u know if spark plug is bad I didn't understand

[@8020Media]

T - If you look at it, you could tell. Or if you have a P0300-P030X code. What vehicle do you have?

[@tyronethomas820]

@@8020Media 2003 grand marquis

[@davidchung4651]

👍🏿

[@8020Media]

David - Hope it helped!

[@electric8668]

A bad ECM/ECU is another possibilty as the cause of misfire.

[@8020Media]

E - Indeed, although, not super common.

[@electric8668]

@@8020Media Agreed