2008 Shelby GT - Misfiring

Discussion in '2005+ Mustang GT 4.6L Tech' started by Zoso, Oct 12, 2021.

  1. Zoso

    Zoso Junior Member

    My Shelby picked up a misfire on CYC 4 - Easy fix - New spark plug got me back on the road. Will change them all this winter. Strangely, the car only has 18,500 miles. I am using MSD red coil packs.

    Motorcraft SP-547
    Gap: .054; w/ Black Coil Boots; Spark plugs are torqued to the proper specification. Spark plugs- SP-546 and SP-547 require properly torqued to 30-38Nm (22 to 28 Ft. lbs.) with a dedicated 9/16 spark plug socket.
  2. 07gts197

    07gts197 forum member

    Get rid of those coil packs they’re garbage.

    Sent from my iPhone using Tapatalk
    DieHarder likes this.
  3. DieHarder

    DieHarder Member

    Agreed, go with stock. I have a good/used set (Black coil boots from a 2006) if you want them that I'd let go for $20 +shipping. Ran perfectly when I pulled them. PM me if you're interested.
    07gts197 likes this.
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