I have a vehicle with a cylinder misfiring (according to my OBD-II code reader). I have decided to have a mechanic repair it, as I have never performed a similar motor vehicle repair.

Note that the only consistent symptom besides throwing the cylinder misfire OBD-II code is a little accelerator hesitation.

Not consistent was also some really bad (perhaps metal on metal - hard to tell) grinding sound for about 10-20 seconds when first driving after not using the vehicle for over 2 months. It sounded real bad, but resolved on its own before I could even turn around and park.

To help me evaluate different mechanics, I would like to know what is likely required to properly diagnose and repair this problem. With the knowledge you provide, I will hopefully be able to filter out the scammers and find a trustworthy mechanic for this job.

  • What are the symptoms you experience? The underlying root causes, and thereby the work involved is difficult to estimate if you only provide an suspicion of the fault
    – Martin
    Nov 11 '20 at 11:00
  • I fixed mine by wiggling the wire to the injector on the misfiring cylinder. Nov 11 '20 at 15:03
  • @Martin Great question! Thank you. I updated my question to answer your question. :) Nov 11 '20 at 17:24
  • Clear the code and drive it for a bit to see if the code comes back. All sort of bad stuff happens if the vehicle is sitting, some of it goes away after a short drive.
    – EᑎOT
    Nov 12 '20 at 15:23
  • @EᑎOT That was my original plan, but the answer for the following question have made me think it could be an undesirable plan: mechanics.stackexchange.com/questions/77548/… Nov 13 '20 at 4:36

There are many reasons for a cylinder misfire, many of them you can check for yourself. Easy to check are:

  • Spark plugs: a worn plug, badly gapped plug or a fouled plug
  • Spark plug not fully in: check to make sure the plugs are inserted properly
  • Spark plug cables: worn, pinched or greasy cables may not transfer electricity properly. Also make sure the connections are clean
  • Coils: it's hard to check these without the right equipment, but easy to replace

Less easy:

  • Cylinder compression
  • Fuel Injectors
  • Fuel Pressure
  • Valve seating

It would make sense to check the easy things yourself and possibly save yourself some money.

  • 1
    Thank you. That is a great list, and as you mention, I can check many of those items myself. Nov 11 '20 at 17:26

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