TEST 9: Other Causes Of A Misfire

Other Causes of a Misfire. Power Transistor Test and Ignition Coil Test 2.4L Nissan Altima (1993-1997)

So you've done all of the spark tests, and still your Nissan Altima is running rough (rough idle) and/or the Misfiring. Well, here are a couple of suggestions that might help:

  1. The valve cover gasket is leaking oil onto the spark plug wells (tubes) and soaking the spark plugs and spark plug wire boots in oil.
    1. Over time, this oil will cause a misfire as the oil cooks and turns into carbon tracks.
    2. The photos in the image viewer show you what a carbon track looks like on the inside of the spark plug wire boot and on the ceramic insulator of the spark plug.
  2. Engine compression test
    1. One of the most overlooked diagnostic tests to find the root cause of misfire is the compression test.
    2. You'll need an engine compression tester of course.
    3. The engine compression readings between cylinders should not vary more 15%.
  3. Carbon tracks on the spark plug(s) and in the inside of the spark plug wires.
    1. The photos in the image viewer point (the orange arrows) to what carbon tracks look like.
    2. Replace the components as affected with carbon tracks.
  4. Broken spark plugs.
    1. This usually happens at tune-up time, if you have dropped one on the floor.
    2. You power washed the engine, this is something that should never be done on any Nissan vehicle.
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Nissan Vehicles:

  • Altima 2.4L
    • 1993, 1994, 1995, 1996, 1997