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WItoTX
Well-Known Member
The plugs out of spec was cylinder 8 (passenger rear). I could be wrong on that cylinder number, but it was passenger rear.
It was the factory plug as best I can tell.
WItoTX
Well-Known Member
Ahh gotcha. I replaced them with the stock motorcraft plugs (SP548). After doing more research, I will probably go the route HB did and go one level colder when I swap them next year. I still have a stock tune, so at least there is one less variable in there to play with.
On second look, the old plugs were iridium's, so They've definitely been swapped at least once, and had I known that before I pulled them, I probably would have gone with the iridium's (SP90) again.
I have a track day this weekend, so if any anomalies come up, I will keep you updated.
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