Mystery coil boot manufacturer

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Sep 20, 2025 | 01:09 PM

BruceCamano

Thread Starter

5th Gear

Joined: Mar 2020

Posts: 5

Likes: 1

Mystery coil boot manufacturer

2015 F350 CC LB 6.2
So I was in the process of replacing coil boots/springs/resistors at 106K miles. Most are clearly Motorcraft (separate coils and resistors), but one has a very different design. The resistor is assembled as one piece with the spring. Compared to the Motorcraft parts, this resistor is in pristine condition.

The coil that this was attached to has zero labeling, so I am at a loss to know the manufacturer, but I would love to switch to this style of coil and resistors. Anybody know where to source these parts? Thanks! Bruce

Sep 21, 2025 | 06:53 AM

techrep

Cargo Master

Joined: Sep 2023

Posts: 2,835

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From: Virginia Beach

try looking on Rockauto at all the selections.

Sep 21, 2025 | 07:01 AM

BruceCamano

Thread Starter

5th Gear

Joined: Mar 2020

Posts: 5

Likes: 1

Thanks, I did that and did not see any that had the resistor “built in” the spring.

Bruce

Sep 21, 2025 | 11:24 AM

2015 F-350

More Turbo

Joined: Jun 2024

Posts: 631

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From: Southeastern US

Has anyone run these coils without the noise suppression resistors installed - found the answer:

Can resistors be left out?

No — you should never delete them.

If you tried to run non-resistor plugs or bypass the resistive boots:

You’d get radio noise/interference in the truck’s electronics.

The PCM’s ignition timing sensors and misfire detection could get confused.

It can stress ignition coils, shorten spark plug life, and cause misfires

Ford specifically engineered the ignition system around resistor plugs + resistor boots (on the top row)