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Diagnose a Misfire LIKE A BOSS (DIY vs “Pro” Mechanic!)

Do It Yourselfer diagnosing a single cylinder misfire on a Chevy Suburban that a “professional” fired the parts cannon at by replacing plugs and wires (pretty much the status quo for hacks, ain’t it?). Can a DIY diagnose it any better without playing the parts lottery?
See these other channels for more great auto diagnostics!
Stuzman (Automotive Electrical Engineering)
Spelunkerd (General fix it of just about anything)

Schrodinger’s Box website:

48 thoughts on “Diagnose a Misfire LIKE A BOSS (DIY vs “Pro” Mechanic!)”

  1. Thank you very much Matt you’re cool awesome video thank you

  2. kirk west says:

    Got a 13 challanger that misses when going into encon mode…that points me into MDS soleniod direction.. No codes and idk how to test them anybody got any input???

  3. You’re legit man. Great job

  4. Roudter says:

    It's a shame that a lot of so-called professionals have given up on trying to understand electronics fundamentals….Ground (sink) switching… mind blower…


  5. jeepjeeplady says:

    Hi! Love your videos very informative and appreciate that you are honest and fair with your customers! Wish you lived in seattle area! God bless you and Merry Christmas

  6. Amin Mombini says:

    Thanks ,i really appriciate you for such a simple and practical test and diagnostic method,
    Just i 've been confuding when you're using the scope,i mean ,i don't know how to set up the scope and trigger to catch the wave form ,do me a favor with introducing a good surce to find out all the secret about how using the scope.
    best wishes.

  7. Nice video bro thank you makes it easy to understand your method of diagnosis! Great to the point diag

  8. Ahmed Shouli says:

    I changed my ecu and 6 coils and still burning coils now after i changed last burnt coil car still hesitates what would be the problem and cause coils to keep burning any help please? G35 2004 manual

  9. Ahmed Shouli says:

    Does a damaged fuel injector burn coil?

  10. Mr F2015 says:

    Was this car giving a misfire code on that cylinder like a P0301 = misfire on cylinder 1 ? If it was a bad injector shouldn't give a injector fail code like a P0202 ?

  11. Rick Y. C. says:

    Hi Matt.

    I have a similar problem but still can not find a solution I have an LS swap in a classic with a PO304 code

    I have a misfire on cylinder 4 I have a good healthy spark but runs the same with spark plug wire plugged on or off

    Next I will blame the injector but I hear it and feel it working. I have also taken it out and made sure it is not clogged.

    – when I unplug the injector plug or remove the spark plug wire the engine shows no differences by doing either ?

    Today I what installed new spark plugs and still get the same code.

    I did also a compression test and I have 150 in all cylinders

    I also have remove the valve cover to make sure the rocker were moving and they are as the rest of the

    In the morning when cold and starts right up like a champ. I will note that after it is warm it will only stay with a very long crank. Almost feels like it is flooded?

    – I checked the pressure regulator and it is dry when I unplug the vacuum ?

    Stupid question but what Should I check for next.
    I guess I can check for leaks with smoke.

    Let me know what you think

    Thank and love your channel. !

  12. nice printed t-shirt i know what it means.😂

  13. Andrew says:

    At last you're using your scope, and in such an interesting way! Excellent diagnostics, and that little test at the very end wasn't excessive in my opinion. Great job man.

  14. Max's Garage says:

    Hey Schrodinger's Box (I realize I don't know your real name) , I am writing an article for my blog about gimmick tools. can you help me think of some more? Or anyone reading this? I am trying write a list of tools that may sound cool, but will just sit in your toolbox and not be touched. I just realize it is harder than I thought to write, because even tools people thrash online somehow still have like 4-5 star reviews on Amazon (even though I would probably never use them).

    Any thoughts on what I am missing?

  15. BigSed176 says:

    Hi I’m new to the channel you’re extremely knowledgeable I like your style Of teaching and explaination

  16. abphaibinge says:

    Hello and yet another awsome movie! Quick question! when do you release your car diagnostic book ? cause you would do the world a favor to make one, and in the meantime do you have any book recommendations about car diagnostic. keep up the good work!

  17. well done – looking forward to the new channel 😉

  18. I would consider a pro someone like South main auto and scanner danner

  19. Timo Wallin says:

    What you dont see with the testligt is the ground-level/control wire condition if your test light dosent draw as much as the scurter.
    I have had 1 bad scurter with bad control wire and sean that flash on testligth…

  20. Hi Mat, just a quick one. I have a Hyundai i20 and there is a check engine light on. The short term fuel trim for B1 S2 is %97 and the Equivalence ratio is 0.95 and I have no direction to go with this. The B1 S1 short and long are 0.2 at idle. Could we interpret something from this? Thanks.

  21. ChadMcFly says:

    Any help car was running perfect changed spark plugs now misfire code changed wires coils boots MAF crank sensor fuel filter no vacuum leaks replaced breather hose injectors working car idles good when warm misfires under load its undriveable

  22. Sam White says:

    Auto part stores must hate you. 99% of their sales comes from part swappers

  23. Hey Schrodinger. I am unable to subscribe to your video membership. Am I a loser or is it that I can not pay for your subscriptions. Keeps declined.

  24. Noid lights in my tool box came to mind during the video. Youre a sharp mechanic.

  25. aiiceejew says:

    This freakin Dude is awesome. He's a trip. Featuring old school with new school applications.

  26. Norbert NN says:

    Hi Matt my friend has a Renault Espace 2.0 turbo 2005 when he brought the car to the mechanic the windscreen wipers wers not working( no power to electricity connection to the wipers motor), fuses were and are good. so the new software to the UHC ( one of three contents od the Comfort Module ) was installed. After that the wipers are working, but there is no connection with climatronic now( not even a display). Shoud there be another software installed now, or should we check in other direction? Thanks

  27. Have a query, maybe you can settle this, a statement you made a while back, about turbos. Turbos in my mind are dirty and not as practical as everyone makes them seem. Unless your drag racing or pro racing, then sure. Personally I would rather mess with fuel cells and computer mods and the likes than add a stupid expensive turbo. Like most cars these days are only stock hp and can be easily modded without the extra expense and time of turbos. According to emission standards turbos are not allowed for prolonged use anyway, practical only under light loads and not really better on fuel economy. Infact worse on engine and fuel and dirty. What are your views. It is a sore topic for many. kudos.

  28. Rob Mut says:

    Great example of using all your senses to troubleshoot. They can all come in handy. Well, except maybe for taste.

  29. Simon flores says:

    when is the pay channel starting let me know

  30. Nicely done Matt . Two terrific mentions and congrats on 100K , you have put in lots of hard work and have had lots of fun along the way too . Cheers 👍👍

  31. Lennox says:

    Hi , but how about to run compression test as well to see how well is the Engine's components ?

  32. Robert Smith says:

    Matt can i ask you a question about my 2004 pontiac grand prix?my gas gauge ghost from Full to empty after starting the car. I've replace the fuel pump but it still doing the same thing, could it possibly be in the wiring? Or what are the odds that it's the gauge itself?

  33. Hey Matt,

    Any updates, well I have one for you. I have been saving money so I can quite my job. Probably should go into business for myself…. Well anywho!. I took my car to 3 mechanics 3 separate occasions could not diagnose or fix the problem. They all went for manifold leak, could not find it right. After watching your videos, even I knew it was not a manifold. Just focus on this point which is, that it, did not have factory but after market parts. Well kind of left me with my head up my arse. (Confused). In fault finding. for 6 months, It literally took a 6 months. No check engine light and from knowing nothing at all to finding and fixing the problems. I just regretted putting chemiweld in. Everyone hates when I tell them. Do not use CHEMIWELD even mechanics 'such a red face', lol., it is just a mess, and blows heads. See why I regretted it. because someone told me too. I hate that. You saved me alot Shrodinger, "Thanks alot". "O' yea is a orange spark any good how to fix, no vids, should I use 0 ohm resistance leads. You should make a vid"… Please, explain.

    had a whole plethora of issues. wells some, oopsie, lol. Geez, ok, Well I know now. [SOLVED]. You want believe it!.
    Your AWESOME.

  34. Bilo Bicho says:

    Nice very good info 👍

  35. shayla ledet says:

    2003 dodge bank 1 lean but only has o2 sensor before and after cat only 2 sensors it
    y pipes together

  36. Sean Bruce says:

    Love the channel. Checking the injector eliminates poor terminal tension between injector and connector, nothing like having a comeback a week later on something you were positive about.

  37. neppy5 says:

    Matt, I desperately need that advanced channel…. TAKE MY MONEY NOW!!!! i’ll throw in my first born son too

    Fair warning that he will pee on you during diaper changes

    Thanks for taking the time to share your knowledge and produce helpful content

  38. Love the shirt, only from a scientist! Oh yeah, great video too!

  39. Bill Kendich says:

    You're a mechanic people could trust you with their cars. Good job.

  40. after I did all plugs and coils on my f150 I had a misfire….I was like wtf..turns out I dropped a plug and bent the ground strap just enough to cause problem but did  notice before I installed it.

  41. Hi Matt, another great job! May I have your ideas about what can cause my car to start almost instantly with almost no crank when cold? (but not smooth for a few seconds) Can Leaky injectors cause this? It cranks and fires normal when hot. Beside that there is a slight intermittent shake at idle with no misfire code and ltft shows negative 3-7%. thanks.

  42. Nice work Matt u rocked that brother.. Do u have a Facebook account id love have u as a friend

  43. Ok I watched the video now I must troll the comments for the experts diagnostic

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