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Apr 25, 2020 | 10:55 AM

Corey Allen

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Help

Got an 03 6.8 with 234k. Miss at idle but other than that runs great. Noticed fuel mileage decrease but have replaced #10 COP plugs and new boots. Any suggestions would be appreciated. I do run sea foam and have replaced pcv valve and fuel filter within last 2 months. Air filter is new as well. No codes either.

Apr 26, 2020 | 11:26 AM

krewat

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From: Long Island USA

Did you replace all 10 plugs? Do you still have them so you can take a picture and show us? One of the best indicators of how each cylinder is running is the condition of the plugs.

Apr 26, 2020 | 11:54 AM

Corey Allen

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Yes. Replaced all 10 plugs and boots. Plugs were ashy and had about 90k on them from talking to previous owner. (Close friend)

Old plugs.

Apr 26, 2020 | 01:28 PM

krewat

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Nice, and normal... looks to me...

What were the #'s on the plugs?

Apr 26, 2020 | 09:16 PM

Corey Allen

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You mean the gap? Or part number? New plugs were champion and book said to gap at . 054

Apr 27, 2020 | 02:08 AM

Bently_Coop

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Motorcraft or Autolite is typical for Fords. Champion for Mopar.

Did you replace the boots and springs? Any aftermarket coil packs? Denso is recommended for COP's. Have you cleaned the MAF sensor?

Apr 27, 2020 | 11:14 AM

Corey Allen

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Quote:

Originally Posted by Bently_Coop

Motorcraft or Autolite is typical for Fords. Champion for Mopar.

Did you replace the boots and springs? Any aftermarket coil packs? Denso is recommended for COP's. Have you cleaned the MAF sensor?

All plugs springs and boots replaced. #10 coil replaced with NAPA coil. I recently within the last 3 weeks ran sea foam through the vacuum line (brake booster) due to pinging when acceleration. Helped but within a week came back which led me to replace boots springs and plugs. Also just dumped two cans of sea foam into gas tank. 27 gal of gas. Pinging is gone now after plug replacement.