alcohol gas
2 Answers
I would agree if it was made in 2010 or later if you hear a tapping you might have to use a higher octane gas ethanol evaporates from the gas lowering the octane (ethanol is used as an octane supplement) causing a tapping sound in pre 2010 model engines and change your fuel filter more often as ethanol also absorbs moisture then leaves the moisture behind as it evaporates)