2005 Ford Mustang 4.0L with engine code P0456 and fail emissions
if you have a P0456 the first thing to do is replace the gas cap and reset the code. Keep in mind the car has to be driven until the monitors are complete after reset the code. I would have 10 to 15 miles with at least 7 miles of highway driving at 60mph.
did the smog tech test the gas cap?
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