Al Kohalic

I would recommend you watch the whole thing, but what you are looking for is at 9:09 of the video.

RLXXI

Watch the video but run like hell away from Autolite anything. Go Motorcraft for quality parts.

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Al Kohalic

I will agree with you on that.

Snowflake

Funny auto lite makes motorcraft plugs.

Al Kohalic

No they don't. Not the iridium ones. NGK does. Confirmed by NGK and Ford.

Snowflake

Maybe in the US unless it changed up north it WAS Autolite for years. Replaced hundreds with Autolite iridiums over the last few years with zero problems.

911/996

Bad/weak coil likely resulted from water ingestion that raised the effective compression ratio so high that the spark jumped inside the coil often enough that a carbon path formed.

papa tiger

Iridium comes off as being a stronger plug but is weak and like porcelain china. When they start to fail the truck bucks a little on slight up grades under cruise. Keep it up and u damage a COP or more. I would look at plugs better suited for blown conditions and change more often. Those long lasting steady upgrade pulls are hard on M. Think of it like leaving work by the river bank and driving steadily uphill to Suburbia 6-10 miles away at rush hour.