Handbook says:
FUEL RECOMMENDATION
Use unleaded premium gasoline with an octane
rating of at least 91 AKI (Anti-Knock Index)
number (Research octane number 96).
If premium gasoline is not available, unleaded
regular gasoline with an octane rating of 87 AKI
number (Research octane number 91) may be
temporarily used, but only under the following
precautions:
Have the fuel tank filled only partially with
unleaded regular gasoline, and fill up with
unleaded premium gasoline as soon as possible.
Avoid full throttle driving and abrupt acceleration.
However, for maximum vehicle performance,
the use of unleaded premium gasoline
is recommended.
CAUTION
Using a fuel other than that specified
could adversely affect the emission
control system, and may also affect
the warranty coverage
and
Octane rating tips
Using unleaded gasoline with an octane
rating lower than recommended can cause
persistent, heavy spark knock. (Spark
knock is a metallic rapping noise.) If severe,
this can lead to engine damage. If you
detect a persistent heavy spark knock even
when using gasoline of the above stated
octane rating, or if you hear steady spark
knock while holding a steady speed on
level roads, have your dealer correct the
condition. Failure to correct the condition
is misuse of the vehicle, for which NISSAN
is not responsible.
Incorrect ignition timing will result in knocking,
after-run or overheating. This in turn may cause
excessive fuel consumption or damage to the
engine. If any of the above symptoms are encountered,
have your vehicle checked at a
NISSAN dealer or other competent service facility.
However, now and then you may notice
light spark knock for a short time while
accelerating or driving up hills. This is no
cause for concern, because you get the
greatest fuel benefit when there is light
spark knock for a short time under heavy
engine load.
So using 95 regularly is not recommended but whether 1 octane lower than recommended is responsible for blown engines ............
That said, we are certainly hearing about more engine failures as mileages creep up