octane boost wont do a thing for the 4.0L unless you have increased the compression ratio, or your engine is dirty (carbon deposits) which effectively increases the compression. The Jeep 4.0L system is designed to run on basic 87 octane.

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99 XJ Sport 2 Door, 4.0L, 5 speed, all stock. Daily Driver
79 F150 Standard Cab Short Box, 400ci, NP435, NP205, 35" SSRs