Engine Misfire? Trouble Code P0303 Meaning, Diagnose Spark Plugs & Ignition Coils 

This video keeps on giving 3 years later. :D This trick helped me out immensely and I was able to get a new ignition coil and solved the problem. Thank you very much, 3 years later, for having made this video.

This girl is awesome! She is always detailed and to the point using common sense! Great work Sue!

Garage swapped 4/6 of my coils and I had to take it back 2km up the road as the 2 others died. My mechanics should have swapped all coils like she mentioned! Great advice.

I'm confused as to why you moved the coil AND the plug to cylinder 5. Moving only the coil would have narrowed if further, if the misfire moved, bad coil. If the misfire didn't move, bad plug.

I think you did a great job in explaining your break down of the issue. Thank you!

She has a great way to communicate things that are complex and difficult, unless you have them explained by someone with above average intelligence like her. This is awesome.

Anytime I see Sue I click play. Clear relatable instructions. Socket size and torque specs!

My sons 2005 honda civic lx threw a po301 code (cylinder 1 misfire). I want to pinpoint the problem. So I swapped coils 1&2 first. Then cleared the codes. Once engine light comes back then I will see if I get po302 code. If yes then the coil is bad and will replace. If not then I will swap the spark plugs. Clear codes again check the codes. Swapping plugs and coils at the same time will not pinpoint the problem.

Funny enough, but both times 2 different trucks i had a P0302 code it was the injector, the o rings were gone. new o rings, no code ran great, so also worth a check if you're having a hard time finding what is causing the code. yes i swapped coils over side to side first, then plugs.

Sue is amazing. I can't tell you how many issues her videos have helped me with. How to troubleshoot, buy the part and fix it. Great resource. Thanks again Sue

Great job simply explaining the real issue.👍

Love this This channel and love your clear and direct explanations!

Straightforward explanation of a basic misfire condition. Simple things first before throwing the parts cannon.

you do such a great job! Thanks for taking the time to educate us!🙂

She’s a real pro! Great explanation

Great video. I have a 2005 Dodge ram (200,000 miles) was getting skipping a good bit off and on. It got pretty bad so I bought 6 new spark plugs had a mechanic change them, I figured after that many miles it needed them. Seemed to work then got real bad 2 days later. Still getting P302 code. I bought 6 new ignition coils and asked him to just change them all instead of the bad one. Runs like a sewing machine now. I think that coil had been cracked or something because it was intermittent for years. Maybe changing the plugs disturbed a loose wire of something. It's good for another 200,000 now.

Thank you so much! I'm having the same issue with my engine and I've done so many other fixes and hopefully when I change the spark plugs it'll be fixed. I fixed vacuum leaks, changed the EGR valve, changed the TPS and now I'm going to change the spark plugs. Thank you again for showing an example of the problem, that made me appreciate this video a lot.

Great video! Yes, if you have a Ford product (Taurus, Windstar) with the 3.8L V6, it doesn’t have coil over plug, but rather has an ignition coil six-pack. After only 110K miles, the dreaded P0303 code came up, and…it was my ignition coil pack! No wonder everyone stopped buying Ford cars.

I exchanged the coils &plugs from cylinder 3 to 1 and still got P0303 after I erased the code

I just had a misfire code. Changed sparkplug and coil pack. Misfire was still there. Decided to go out with the scan tool and clear the code , turned it off and back on and had no more misfire. Hopefully this helps someone in my situation.

Thank you for this video 🔥 it helped me a lot fixed my problem with out costing an arm and a leg

Very well explained..thank u..my project for tommarow

Great explanation. Thank you from Montreal, Canada

GREAT JOB DOING THIS ANALYSIS

GOOD PROBLEM SOLVING SKILLS, NICE JOB.

FOUND THIS VIDEO AFTER SPENDING $380 ON CAR PARTS THAT I DIDN'T NEED. THIS LADY IS AWESOME WISH I HAD FOUND THIS DAYS AGO.

Great tips! Merry Christmas 🎅 🎄

Just got a po302 on my 2006 Subaru sti. 1st time. Cleared it . Gonna test drive if it comes back gonna do the swap

Great video as always! Thank you.

Excellent educational video. Really appreciate the presentation and the detail.

Good job . I can respect a women under the hood and she knows what she's doing

Thanks for the video and explanation 👍

Thank you very much! I got that problem with my 2012 f150 ...

Great video. I just think if you swapped the coils first, then the plugs. This could be either the coil, spark plug, or both.

When you're working on your friend's car and your mom comes out and fixes it. 🤣

I have the PO303 code on my 2002 Dodge Dakota with the 3.9L in it. I have changed the plugs, wires, cap, rotor, and ignition coil and the check engine light still goes on and off. Any ideas? Help...

Dr. Sue will take good care of the patient.

I love to watch her teach us she's Great , Blessings to you all Amen 🕉️

Why did you recommend replacing all the coils if the coil you first looked at looked good. The spark plug looked dirty. Why not clean or replace that plug?

Thanks.Great useful info.

Thanks Madam dor the clear explanation

Good job explaining 😘

Thanks for sharing this video

Big help ..thanks

She s awesome. Thanks Sue!

great, thank you for this video.

Thanks for the video now I need to check my car out 😎👍🏾

Great video, good information! 👍🏿

Hi Dear,How to clean Engine Lexus RX 350 2010 and should cover for not damage parts of Electric system thanks for answering my question.🙏🌹🙏

If there is excess oil on spark plug. It could be a damaged Valve Cover Gasket, that's leaking! .You r going to get the same code P0303. I had same problem with a 2006 GMC Canyon 3.5. Replacing Gasket fixed the problem. I'd suggest to replace factory original spark plugs and coils, if they r old. On the Gasket, just don't buy the cheap one! 😁

Im your fan good explain and easy thank you.

I got a Code P0302 in my 2015 Jeep JK . Pep Boys recommended all new coil pack (6) and spark plugs (6).

I changed all it still missing

I just switched all the coils and spark plugs on my mazda. And it gave me misfire . I. Gonna what you just did thank you.

Normally, I don't really want to say anything about these tutorial video unless they are really wrong. In this case, I don't agree with the way she try to diagnose the problem. Here are the orders to check when the engine misfire on any of the engine cylinders: How to repair car engine error failure code p0302 Replacing spark plugs that are defective or damaged Replacing spark plug wires that are damaged Replacing coil pack wires that are damaged Replacing EGR valves or tubes if they are clogged Replacing valves that are burned Repairing any vacuum leaks Repairing or replacing leaking head gaskets Replacing camshaft sensor if defective In this case of a P0303, it is the third cylinder that the engine sensor detect it has misfired. As she has shown the sparkplug, it is probably worn and should be replaced. She should replace that spark plug first before doing anything else. If the engine runs fine after replacing the spark plug, the problem is solved. In diagnostic, you don't ever change more than one part of a time, then you don't know which one is the real problem. Swapping both the spark plug and the coil pack to a different cylinder do not tell you which was at fault, the spark plug or the coil pack. In this video, the spark plug in the fifth cylinder looks like brand new, it probably never seen any spark. In a typical engine, all spark plugs would be likely covered with black carbon and the gap varies between spark plug to spark plug. The first thing that she should check is the spark plug gap on the misfire cylinder and adjust it first. If the spark plugs have been in the engine beyond the normal maintenance interval (105K), they should all be replaced but you could just adjust the spark plug gaps to get by until you get the new spark plugs. If replacing the spark plug or adjusting the gap does not solve the problem, the next step is the coil pack that may be bad. One way to check if the coil pack is bad, is to disconnect the wire from it, and the engine does not behave any different, then the coil pack is bad. You can use the list of progressive diagnostic steps above to check for the next culprit that generates your P0302 or any other P 030x engine codes. Good luck!

I just bought new coil packs from you all. I was trying to remember why the website name sounded familiar 🤣

Why would you swap spots? Put a new set of plugs. If that handles the problem your done. You could ohm out the coils if the plugs didn't fix it. I don't understand swapping parts when the plug is wet

Before she restarted the car she said to clear the code and see if the misfire transferred over to cylinder 4 even though it was cylinder 5 that she swapped with. She did correct herself after starting the car, but thought i'd point that out

thank you so much...

Good job mam

Very interesting to watch. I have a 2012 Sentra, so I won't be doing this.

You miss-spoke at 4:03 and said cylinder 4 instead of cylinder 5. Also, why, would you replace all the coils, instead of the one you determined to be the problem?

Great help!

Greetings, 👋🏼 I have a 2018 Toyota Tacoma SR5 truck and I wanted to know what should I change if my vehicle has 37,776 and havent changed anything yet and it's a used vehicle from a used dealership? And I found out they didn't do the transmission oil change. The only thing I changed was the airfilter and oil change at the Toyota dealership.

Went to my usual shop and the manager tells me I need all new coils and spark plugs. I had new plugs put in 13000 miles ago, and the car drives 2000 miles a year. The worker said that the bolt holding the coil in the misfired cylinder had to be cut out and that could damage the coil. Even if that is the case, recommending replacing everything without even doing this simple test sounded to me like a blatant money grab. That's like having a hurt finger, but the doctor doesn't X-ray you and tells you lets cut and replace all your fingers.

Very nice presentation. Seems like a pretty cool gal 🤘🏼

What's the name of the diagnosis kit you are using please?

Thank you very much ❤❤❤

all great but how are you going to determine if it is spark plug or coil if you are swapping them both at the same time??? isn't it obvious to swap the coil first? to know if the coil is bad or good? and then proceeding with spark plug ? of, course it is best to replace both at the the same time, however for the purpose of identifing the 'usual suspect' do the coil first,,,, that's my take on this simple issue,,,,

Hi Sue, great video. I have a 2009 Lexus RX 350 V6 and I keep getting a P0333 error code which usually means a problem with the knock sensor, however, my mechanic said that it could also be a buildup of carbon in my engine and he recommended that we try using SeaFoam additive in the fuel tank to slowly get rid of carbon buildup. The SeaFoam has definitely made a difference in performance, and I only use octane 91 on a daily basis. After clearing out the P0333 code, I drove for a whole day without any issues, and the engine is still smooth, quiet and no knocking, but then suddenly I will get the P0333 code back on, creating an "Engine" and "VSC OFF" code to appear on my dashboard, and of course reduced performance. My mechanic is convinced that my knock sensor is fine. Is it possible that the problem could be related to a vacuum leak or a problem with my wiring? Do you have any suggestions?

I had this problem on my Mazda 3,I did the exact same thing. Same results, So I bought all new plugs and coils. 87 miles later the problem is back🤦

P0305. I changed the coil from 5 to 7. Replaced the spark plug. Still reads p0305. Should I disconnect the battery? Or is it still misfiring ?

I’m having same issue p0303 misfire on cylinder 3. Changed the ignition coil and code went away then 30 minutes later came back. Also have a p0031 code for oxygen sensor. But when I changed my coil it had oil on it? Does that mean I need a valve cover gasket??

I would like to know what kind of scan tool are you using to diagnose code 303. Iam interested in buying a good scan tool that I don’t have to pay a lot for updates.

Ok so I cleared the codes and moved coil and plug to different positions but i am still getting a p0303 when I pulled the plug it looked and smelled of antifreeze but no other plug or coil did now what do you think I should do oh I also keep getting a p0135 for bank 1 sensor 1 sensor is new.

Been there done that with a v6 accord. Not a cheap job at the dealer 🤑

What tools are needed ? can you list the name of the tools used individually

pretty good! thank you***

Did you disconnect battery before dis connecting coil & spark plug.

Mine called po305, managed to swap plugs, didn’t help, I had to wait for my father to awaken so I could get his special screwdriver for the cap and rotor. Pre code was o2 sensor left bank. No upstream or down stream, turned out the cap was wore off on the 1,3,5 cylinder.

I am having this problem took it my dealer and 2 other business and they all said have replace the engine. I am wondering if they done all this. I say yes bc hell I do not know. Now my engine light is off and still getting the same diagnosis. I been driving locally and not far lol. I still think nothing wrong with bc I do way overboard maintenance. Car did not make to 100,000 but this issue cost me alot just to diagnosis and me saying no I might else get a new car.

❤ hi sue. Is it ok to replace just 1 bad ignition coil and spark plug on this repair

YYEEPP swap coils/plugs to see if the problem follows.

Mine does not have the cel on, but there is a misfire cyl 2. the plugs are new, and swapped coils, still misfire cyl 2. Any ideas on the next step?

Awesome 😊

I have a 2008 Chrysler Sebring Convertable 6 cylinder. I had taken it to get a tune up and fix what seemed to me to be a spark plug that burned out while I was driving it. While driving it, I began to smell burning oil and then the sound of the car was different. The men that I took it to said that they could fix it and give it a tune up. I picked up the car and brought it home. Later in the week, I drove it to Walmart. The cylinder began to do the same thing it did before it was "fixed". I cannot afford to take it back to the same place since it doesn't make sense that I would pay them twice to fix it... What do you think could possibly be wrong with it? I'm in Anaheim, CA and need to find a reputable garage to fix it and make sure that I'm not taken advantage of.

IA Auto I have a 2005 Nissan altama i am getting the engine code P0302 and a service engine soon light would that be the spark plugs or ignition coils

I have rav4 model 2009. Error in cylinder 3 when I reach high speed or climb high level. Changing sparks and coils plus swapping injectors but still same code. Checking cylinder 3 compression is ok.what do you purpose please.

Changed the plugs, wires and coil pack on my 07 f150, 4.2 liter. Now it’s showing a code P0171. What can I do to bypass the 02 sensor??

Thank you so much I was so scared when I got code p0303 after changing the spark plugs and so I did the boot swap with cylinder 2 and boom it switched to code p0302 . TLDR it was the boot

I did learn that if you decide to just switch around the wiring harness connector without switching the coils or spark plugs - your car will start jumping when you crank it. But when you switch it back it will work like normal. Does anyone know why that happens ? - are the wiring harness connectors per bay/cylinders specific … example cylinder 3 connector can only work with cylinder 3 and not 2, 1, 4.

Good mechanics are hard to find... I'd absolutely take my vehicles to this one if she were local.

Hi sue i have a 2018 honda accord sport 1.5l change plugs and coils still miss firing code reads p219e maf oxygen sensor what you think oh also say 3-4 miss fire thnk you

Thank you 😊🥰🥰🥰🥰🥰🙏

Had similar code on a Nissan Qashqai, had coil packs and spark plug replaced, no luck, now I'm being told I need to replace the engine. 🥵

Please any take on this will be most appreciated, i have noticed increased in fuel consumption after changing/replaceing my NOX sensor (BMW 1series 116i m sport 2008 e81) and low power. Please comment 🙏

Mantap..

Thanks its was my coil 😀

I would have just moved the coil to find out if it was the coil or plug. good video though

Always appreciate female gear heads. Good video!