my 202 owners manual says 87....
FUEL REQUIREMENTS — GAS ENGINE
6.4L ENGINE
Do not use E-85 flex fuel or ethanol blends greater
than 15% in this engine.
This engine is designed to meet all emissions regulations and provide satisfactory fuel economy and performance when using high quality
unleaded gasoline having a posted octane number range of 87 as specified by the (R+M)/2 method.
While operating on gasoline with an octane number of 87, hearing a light knocking sound from the engine is not a cause for concern. However, if the engine is heard making a heavy knocking sound, see dealer immediately. Use of gasoline with an octane number lower than 87 can cause engine failure and may void or not be covered by the New Vehicle Limited Warranty.
I run it and get great mpg with 35's..
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