Gents,
Most unfortunately for me, my redheaded wife's car is a granite 2005 s-type 4.2 and we run into the same thing.
The only alcohol free gas we can get is a regular grade 87 octane fuel. Although she does get the misfire occasionally, I'm not sure it occurs with enough frequency to change gas.
Would the car run ok on the 87 octane? Or half a tank 87 and half 93 to cut the alc percentage?
Wonder if the fuel change and reducing alc in fuel might make the car run better or help longevity?
Cheers,
Rob