Ok... so this is essentially intended to be a notepad of sorts, to form a plan of attack for this weekend. I will happily consider any and all ideas, so if you have any thoughts, feel free to contribute. I like to think that I have some decent automotive knowledge, but as far as turbocharged and Subaru-specific stuff goes, my technical know-how is much more limited (read: nil).
Anyway, I have a few pressing issues with my new 02 that may or may not all be related. First, and most noticeably, is the terribly erratic idle that occasionally results in a cutoff. This is my primary concern, as I worry about oil pressure dipping and ending up with internal problems. Secondly, I have on two occasions experienced misfire codes (first time all four cylinders, second time two, I want to say #1 and #2). This seems to be accompanied by a slight pop in the exhaust while shifting. Finally, I noticed today on my lunch break that the battery is only holding about 12.0 volts. I don't suspect it's bad, particularly because the alternator is only putting out 13.3-13.4 while under no load.
So, since I discovered the idle issue first, I began to troubleshoot it first. The misfire DTCs became apparent shortly after, which helped to widen my scope a bit while poking around under the hood.
The car has an aftermarket intake and the filter is absolutely filthy. This is a no-brainer, but I have no 2.5" cones at my store, and the filter I ordered hasn't arrived yet. Sadly, I wasn't lucky enough to get the stock cleaner with the car.
*I took the MAF out and cleaned it, even though it was spotless.
*I got ahold of an IACV gasket and cleaned it the best I could, to no avail... although the ECU reset did seem to smooth EVERYTHING out for an hour or so.
--Of course, this doesn't rule a bad IACV out as a culprit... very little short of a known good valve and a fistful of extra gaskets would do that.
*For the heck of it, I pulled a plug at lunch (hooked already it seems... notice the trend here?), and it looked brand new; replaced anyway, will do the others in the next few days.
*Fuel filter is new.
While having a quick look today at lunch, I noticed something that had eluded me before; a nice little pool of oil under the intercooler, right around what I assume is the PCV valve. Uh-oh.
Please correct me if I am wrong, but I'm pretty sure that the PCV runs on vacuum... the same vacuum that runs everything else attached to the intake manifold, turbo included. Unfortunately, the boost gauge in this car does NOT work; this is definitely a problem, and I intend to rectify it if at all possible when I take the intercooler off this weekend.
So, a bunch of oil blowing out of the PCV tells me that either A) a hose in there is busted (please?) or B) the car has jumped timing. From what I've read so far, timing could very well explain the DTCs... however, does this 2.0 not have two timing belts? Wouldn't both cams have to jump in order to throw DTCs from both sides of the motor? I've learned in my time in auto parts that nothing is impossible (two blown brake lights at the same time, for instance), but if this is the case, it seems unlikely.
To make things more "fun," the ECU may or may not have a tune on it -- there's an ECU jumper switch under the steering wheel, and my sleuthing skills tell me that this car was traded in.
Finally, either the previous owner or the lot I purchased the car from left a battery tender cable hooked to the battery. I don't believe that the battery itself is bad, so this is enough evidence to make me want to drop some wires under the hood. It's also enough evidence to make me want to crap my pants. Wiring and I don't get along well at all.
So currently, my weekend plan of attack is as follows:
*Replace/improve every ground I can find, in hopes of... I don't know... increasing outbound alternator voltage? Steadying idle?
*Remove intercooler, get a closer look at pre-turbo duct, slap a new hose (and probably clamp) on PCV valve.
*Fix boost gauge, to see if I can get a better idea of whether I've got a vacuum leak.
*Finish replacing plugs for good measure -- I wanted to do a compression test at the same time, but it seems to me that it may not do much good if the engine has jumped timing.
I know this seems like a tall order for a short weekend, but I more or less knew what I was getting myself into by buying this car. If all goes well, at least it won't be a terribly expensive weekend. If anyone has any insight that might help me out here, please don't hesitate to share. I'll love you long time. I apologize for the novel, but I figure that in most cases too much information is better than too little.