My owners manual states 87 octane, but I can pull up a chrysler 300 pdf(Internet) file owners manual for 2010 model year and it states recommended 89 octane, 87 is Ok. In 2009 versions and lower with the 3.5 Liter H.O. the owners manual states 89 Octane. So did they do something different with engine in 2010? Seems to run smoother and quicker response with mid-grade.
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