I have a 05 GT 4.6 with 123,500 on it.
Had it since 90,000.
I'm having a bad sputtering, not every day, mostly under slower speeds and from a stop.
#7 coil was diagnosed in shop as bad. Problem came back inside of 2 days.
I just changed fuel filter myself, no change.
Car idles fine, No missing
When i rev engine in park engine misses originally then smooths out after a few seconds.

I'm thinking it's plugs and or coils, I'm assuming both are original. I've heard horror stories about changing...

Sputtering issue