Cylinder four misfire

Tiny
ABBYJSAXE
  • MEMBER
  • 1999 TOYOTA LANDCRUISER
  • 4.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 170,000 MILES
Hi! Fourth cylinder in my vehicle is misfiring. My first thought was to check the spark plug (and potentially compression while I’m there). Do you have any videos on how to change the spark plug on this type of car? (Or measure compression)
Tuesday, June 11th, 2019 AT 3:26 PM

3 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Hi Abbyjsaxe,

We don't have a video on this specific engine but here is how to remove the plugs according to the manual. Keep in mind this is specific to the coil but once you remove the coil the spark plug is in the hole these come out of. They didn't have a procedure for removing the plug but again, you will see the plug once the coil is out of the way.

As for the compression test we don't have one on your engine but this is a guide on how to do it. It is the exact same process. In fact, this engine that they are doing this one, is the same style as yours (coil on plug).

https://www.2carpros.com/articles/how-to-test-engine-compression

Let me know what you find and if you need more help. You will want to check compression on all cylinders or at least all cylinders on that bank.
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Tuesday, June 11th, 2019 AT 5:20 PM
Tiny
ABBYJSAXE
  • MEMBER
  • 2 POSTS
Hi! Thanks for the information, I’m going to try and take a look at fixing the car this weekend. Two followup questions:

1. I’m definitely a beginner when it comes to car repairs. Are the spark plug replacements and compression testing feasible for a beginner to accomplish?

2. If only cylinder four is misfiring, why do I need to test the compression on all eight cylinders?
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Wednesday, June 12th, 2019 AT 5:43 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Spark plugs are definitely doable. The compression test is a little more involved. I would read the link about the test that I provided and watch the video. If it is something you feel comfortable with then you can give it a shot.

The main reason for doing all the cylinders are, this gives you a comparison between cylinders because each engine is different and we want to see if one is lower than the others. So if all cylinders are 150 PSI and one is 115 then you have an issue in one but you may find others have an issue as well.

Also, just make sure you disable the ignition so your engine doesn't try to start while performing this test.

Again, if you don't feel comfortable then I would not attempt it on your own the first time. However, if you watch the video and read the guide, and understand what it is doing then go for it. Feel free to post your results if you need help determining if there is an issue.
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Wednesday, June 12th, 2019 AT 10:42 AM

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