I've mentioned it a couple of times, but the Subaru has been a bit under the weather as of late.
It started with a power loss, something that was very subtle but noticeable. When the weather turned nice and I pulled the Mustang out for a couple of days the Subaru sat, and when I got back in it there was a dead miss. I ended up driving the Mustang the rest of the week.
When we pulled the plugs out the number 4 plug was fouled. Number 2 was slightly better, numbers 1 and 3 looked fine. I had Eldest Son change out the plugs and put valve cover gaskets in (the left cover gasket had been leaking for some time) and then change out an O2 sensor that had been throwing a "check engine" light that I had been ignoring for a couple of months.
A fresh filter and crankcase of clean oil and it ran better than it ever had before. When I got it there was a noticeable stutter at the low speeds which was almost (but not all) eliminated with a good tune up. Now that the 02 sensor has been changed the stutter is completely gone. I think it had been in the process of going bad for a while and it had been the cause of my previous problems with it (a "check engine" light that called out an Idle Air Control Valve, which going by the price must be made out of platinum plated diamonds. I got one off of Ebay for about 20 bucks that fixed it for a while, but it came back, and then the old one fixed it).
A couple of days later, sitting at a stoplight on the way to work, it coughed once. It sort of startled me, it had been running so smoothly for the past couple of days, but when the light turned green it took off without a hitch and did not stumble again at the next light. I figured it was an abberation and put it out of my mind.
On the way home, however, every time I'd come to a stop behind the school bus I was following it would idle fine for about 30 seconds and then start to cough and stumble. It would run fine as long as it wasn't idling, but it surely didn't like to sit still for long. When I got in it to go to work that night, however, the power loss (but not the light!) was back and the miss was evident from idle on up.
Eldest Son pulled the plugs out of it and sure enough that number 4 plug was fouled again. We cleaned the plugs and I got a set of spark plug wires for it and the stumble was gone again. I drove it this morning out to Range Partner's place, about 50 miles away, and it was fine out and back.
We will see how it does this week, but I think it's back to 100% now.