On my wife's Lexus (Toyota 3.5L V6) it's specified to run on 87 octane, but I swear every time I've filled with 87 the car ended up feeling sluggish, like the throttle response was somehow muted a bit more. Now that I picked up a Jeep with the 3.6 Pentastar rated for 87 octane, I'm wondering the same thing. I totally get that they're probably programmed to run acceptably on 87 octane, but do things like throttle response possibly get adjusted if higher octane gas is used? I know Mazda specifically advertises two different HP ratings for some of their engines, acknowledging that you can run 87 no problem, but that the ECU will dial up/down based on what's in the tank. I'm wondering if other manufactures do this but just don't communicate it.