Plugs: Switch to NGK copper, it's a better conductor, and go to a series 7 plug, it is a colder heat range and therefore will burn hotter. That 16 degrees is your ignition timing, which is regulated by the position the distributor is in, if too low of timing the car will be very sluggish. Kinda sounds like your problem.
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2015 Ford Mustang GT Fastback - Ingot Silver - 6M - Performance Package - Gibson Catback, JLT CAI, FR 47lb injectors, BAMA E85 tune, Eibach Sportline, BMR wheel hop kit, UPR oil separator, Steeda shifter bushing/bracket
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