Dont know if that helps or not but im dealing with the same issue. just had the walnut blasting done last weekend and i still get a slight misfire at idle so im going to try plugs next.
if i were you i would go ahead and do the walnut blasting though, that might fix/help your issue but if not its still a good maintenance that should be performed and you will definately feel a difference.
shop around for the service too because i feel really bad for all of you people paying $400 and up for it lol. got mine done for almost half of that