Are you using a USDM or JDM ECU? The USDM ECU would look for an ELD, but I don't know if that would cause it to not start...probably just throw a CEL. Definitely check and recheck all of your grounds. Did you do anything else before the swap maintenance wise...like a timing belt?
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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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