Finally, with the "stutter" happening fairly regularly, my Subie Guy diagnosed the problem as 2 coil-boots failing. Apparently, with the AC running, at idle there was enough load on the motor to cause it to worsen, and he could hear them snapping from under the car when running. After replacing one of questionable age/condition previously I just bit the bullet and replaced the set. Let me say the driver's side was a beotch, even with the battery out!!! The coils weren't so bad, but the connectors were a bear to reach, and release, with room for only one hand and needing 2!!
She runs like a new car!!! Purrs along like a big happy feline, and I'm one happy camper, minus $502, of course. Now I can do my Stage1 install, and start saving for some Koni's!
Glenn