No. The octane ratings for all grades was the same then and
now. They changed the display on the pumps by using the
average of the research and motor octane ratings. If it was
a regular fuel engine before, it is still a regular fuel
engine. If the engine has collected a bit too much carbon
over the years, it may be experiencing what is commonly
called octane creep such that it will need a step higher
octane gasoline to prevent detonation or "ping". That said,
a little "ping" is not bad for an engine as it can help
reduce the rate of carbon buildup. A slight "ping" of short
duration is also one indicator that the engine is near
optimized for best performance and fuel economy.
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