Your misfire could be bad plugs, from looking at these pictures your plug gaps look massive. NGKs are good and motorcraft is also good and I wanna say cheaper from RockAuto.
Best Spark plug for Ford Mustang
Autolite or Brisk plugs with stock gap.
I have a 05 with Edelbrock SC, 11 pounds of boost, and E85.
I use NGK on my supercharged Roush. The recommended for supercharged engines is 28 to 30k miles. The only thing that you need to research with the e85 tune is whether or not you need a hot plug or a cooler plug. Roush calls for a cooler plug
For spark plugs I always used NGK because that's what Motorcraft actually uses if I remember correctly. Autolites are complete garbage and always fouled out the few times I used them.
Denso TT iridium are so far the best ones I’ve tried in terms of performance
I used to run NGK tr55's in my mach1 but for some odd reason they had a tendency to become loose I thought it was my heads but I switched to a brisk plug over 30k ago and haven't looked back I will be buying them for all my cars.
I replaced my sparkplugs, and everything went smoothly except for the front plug on the driver's side. All the other spark plugs screwed in with little to no need for a socket wrench - except for tightening at the end.
This one plug seems to be stuck halfway down the middle of the thread and won't go deeper unless I really torque it. When I took the new spark plug out, I noticed that the tip was bent with the spark gap being much smaller than the other new piece.
Don't buy Autolite spark plugs. They suck. I had 2 out of 4 in a pack that were faulty and failed within days of installing them.
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