Just curious. How do you go about isolating which cylinder has an issue if you're using something like an o2 sensor? The sensor is usually plumbed after the exhaust pipes are combined so you're getting a combined reading. How do you tell which cylinder is lean if you get a lean reading? Based on this thread it looks like you could use an infrared pyrometer to check each exhaust pipe next to the port on the head and the one running hot is the culprit. Are there other methods? Just looking to gain some knowledge for future trouble shooting.

Thanks.

David
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Spark plugs are good thing to check for rich/lean conditions.

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