The crank position sensor on a Subaru FB engine is, unlike any other car that I've ever seen, in-between the engine and transmission.My guess you have faulty crank position sensor problem. You can try replace with your spare ones, and see if the random misfire error disappear. If you replace it
and there is no change at all, i think the data logger is needed to pinpoint the fault.
What makes you "guess" that it's the crank position sensor?