Spark plugs

B.BASAEED

MEMBER
1996 LAND ROVER DEFENDER
3.9L
V8
4WD
AUTOMATIC
124,000 MILES

I left my car in the garage for inspection, after 1 week the mechanical guy told me that he discovered fuel injector seals in bad condition so he replaced them with new ones, also he checked the spark plugs of the engine and he changed just 1 burned spark plug leaving the other old ones.

I told him I will take the car for a while until I get quotation for the full inspection.
but "once I switch on the car I felt like it was shaking more than it used to be specially on stop or low speeds. (The sound was for every 1 or 2 second interval I was feeling the shake harder) and the exhaust was jumping with the sound too.

So is this problem came by replacing just 1 spark plug while leaving the others or he installed bad spark plug that is not suitable for the engine?

Thanks

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

This is possible. However, are you sure he replaced just the one or did he think you were going to replace all of them? Either way, I would start with replacing the plugs and go from there.

Here are some guides that will help with this including a video to determine which cylinder is misfiring:

https://www.youtube.com/watch?v=QTE8k06MzwQ

https://www.2carpros.com/articles/how-to-change-spark-plugs

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Below is the process from the manual of a like vehicle. Unfortunately we don't have a manual on this vehicle so I can't provide the specifics but this material should get you what you need to replace these plugs. Thanks

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