93 Octane Leading To Rough Idle And Near Stalling?

The higher octane will burn a little colder but shouldnt have the effects you list. I would run some dry gas in the tank, sounds like the fuel you got may have some water in it

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In theory you shouldn't have any problems going to 93.
However the difference between high and low octane is that the high octane is LESS volatile.
Contrary to what the gas companies would have you believe, high octane only HURTS your car and your wallet unless your car truely NEEDS higher octane. Most people buy it because they 'think' it will help something, but it's just a sales gimmick, and higher octane can hurt more than it helps.

My thoughts are that IF you have this much trouble, and it is because of the lower volatility fuel, then you have other issues.
I wouldn't jump directly to that conclusion though, it's probably more likely you got into a bad batch of fuel.