[gefinley]

Good evening everyone,

I picked up a 2000 Outback with 160k miles last weekend to replace my 1999 Legacy that decided to chew itself up, and of course it has now decided to cause me problems of its own. I've spent a few hours reading through previous posts regarding similar issues, but I've had a couple different circumstances that I thought might help narrow down the potential problem and fix.

Sequence of events:

• Saturday - Bought car, drove about 200 miles home with no problems
• Monday - Oil change and alignment
• Tuesday - Around 400 miles of freeway and winding two-lane roads, flat and hilly, no problems
• Wednesday - Out running errands, fine after first stop. After second rough idle and lack of power appears along with CEL. After circling parking lot turn car off, redo gas cap and the problem disappears, CEL included.
• Thursday - Leave early to go skiing, no problems on 100 mile drive up hill. After getting ready to leave, issues return with flashing CEL. Try gas cap multiple times to no avail. Finally poke flap in on about the fifth try, CEL stays solid and car runs fine for drive home. Thought it might be something related to elevation change between my house and the resort.
• Friday - Go to move my car in the driveway, problems are back again. Tried the fuel cap periodically throughout the day with no change. Reset the ECM using the battery/brake method, CEL disappeared but idle/power remain the same. Also smells very rich when I start it.

From what I've been reading on here and elsewhere, it could be any combination the knock sensor, O2 sensor, vacuum hoses, battery/alternator, ignition coil, plugs/wires, PCV valve, fuel filter, fuel pump, fuel pressure regulator, grounding wires, and probably something else I've read and forgotten. The answer has also seemed to be varied with cases.

Sorry for the novel, but I figured I'd try to get as much information out as I could off the bat. I have no records except a CarFax from before I bought it, but it states both the alternator and fuel pump have been replaced since 100k miles. The scheduled maintenance also appears to have been completed at a dealer. I'm unfortunately not terribly well equipped at my house for much work.

 

[rasterman]

I suggest that you start reading out the error codes instead of just clearing them. It's either that or start replacing all the parts you named until you get lucky.

 

[gefinley]

Unfortunately I don't have a scanner at the moment, which I now realize is shortsighted, but I don't want to drive anywhere since the CEL had been flashing earlier today. I'm going to go over the vacuum hoses more thoroughly tomorrow, and see what I can do about getting a scanner.

 

[SubyTechJoe]

I suggest removing the wires from the ignition coil, I suspect you will find corrosion on terminal(s) if this is the case you can try and clean the terminals, and replace the wires and spark plugs.

 

[H-D]

Was the drain oil suspiciously thick? Might have been hiding a problem which recurred when the proper viscosity oil was reverted to. Thinner oil caused an intermittent fouling of plug, miss, reduction in power, & a solid CEL. Seen it before.

 

[gefinley]

As far as I can tell there was nothing off with the oil. Today was new plugs (NGK), ignition wires (Subaru), and battery. The plugs were a bit rough, but not terrible. Ignition coil was in good shape. The car still feels the exact same, unfortunately, and based on the exhaust is still running very rich. Could a loose exhaust be causing this?

 

[gefinley]

Now that I've gotten it figured out I wanted to follow up so it'd be around for others, even if it is a bit delayed.

I ended up having to get it towed to the dealer since I didn't have the time to go through things myself. It turned out to be the ignition coil as was suggested, which is what I get for not really having diagnostic tools around.

Thanks everyone who offered suggestions, hopefully next time I'll be able to figure it out and fix it myself.