Well, possible cylinder misfire issue. 200 Outback Limited, 2nd owner, currently has 170k. 1st owner kept up with maintenance very well, we have put about 25k since we bought it. I began noticing a misfire a few months ago. Seemed like it happened mostly at highway speeds when trying to accelerate, say for a pass or after deceleration due to random idiot conditions. CEL was on, was getting a random misfire code so I replaced the plugs, wires and valve cover & plug hole gaskets as they were leaking oil into the plug holes. I used aftermarket wires from the local parts shop. Problem almost went away, definitely improved, but over a few weeks it came back. I just replaced the plug wires again with Subaru parts and again the situation improved but didn't completely go away. However now it seems like it happens at lower speeds/RPMs rather than highway speeds. How robust is the coil in this car? It is the next part on the "Misfire diagnostic" list. Just looking for some feedback on potential/known alternate problems I might be facing.
Thanks