Spark plug wires, boxer engines, rough idle

[MunkySpunk]

Hey folks,

I just got a 2004 Baja 2.5 turbo with 51K on it. I've got a couple of questions and an issue to sort out.

I normally know my way enough around a typical engine to get sensors, plugs, sending units, wires, fluids, and brakes changed. I'm a wiz with car audio. I've never worked on a boxer engine before.

I was changing my battery the other day to a better one when I took a closer look at the spark plugs and wires. What I saw looked like this video at 50 seconds.

http://www.youtube.com/watch?v=T-pC_dukKZI

I've never seen anything like this before. When I order replacement wires, will I just get the boot portion and I use the wire harness that's already there or do I run completely new wires to the coil pack? Where the hell is the coil pack anyway? Is it under the intercooler? I read that it's on the intake manifold, but for the life of me I can't ID it. Is the wire harness not supposed to be replaced? I looked in the factory service manual for the '04 Legacy/Outback 2.5t and the wires looked nothing like that in the diagram.

I'm also having issues with rough idle and stuttering acceleration at times. Typically my idle is about 700 RPM, but sometimes when I'm standing still it drops off and on, enough to make the headlights dim and the power steering get sluggish. It hasn't stalled yet, but it's trying. The stuttering acceleration happens under moderate acceleration forces, usually in 3rd, 4th, and 5th gears between 2300-3300RPMs. Turbo is spooling up and when the acceleration isn't stuttering the thing has lots of torque.

The CEL hasn't come on at all. I checked the air filter - no problems there. My next thought is the plugs and wires or a vacuum leak. I'd also check the fuel filter and O2 sensor in order of expense. I don't smell any coolant or burning oil, there's no oil in the coolant overflow, no white smoke from the exhaust, and my head gaskets are clean at the block so I don't think it's them.

In the service records provided, I read that cylinder #4 wasn't firing and they traced it back to a faulty injector, which was replaced.

I'm open to ideas.

Could the bad injector have left enough soot in the exhaust to foul the 02 sensor possibly? Where would the more techincally inclined folks here start?

p.s. If anyone has a link or is willing to share a pdf of the 04 Subaru Baja Factory Service manual I'd really appreciate it. The only thing I could find is the 04 Legacy/Outback manual and I've been using that as a reference.

[bulwnkl]

No such thing as ignition wires on your engine. If you find a source that lists them, they're mis-listing something. You can only replace the coil pack assembly. Coil-on-plug ignition is very common these days. Nothing really wrong with it, just different than what you're used to.

I'm not sure what to tell you about your hesitation issue. It is possible that, if the injector was dumping too much fuel in, you've got a ring that's carboned up and not sealing properly (low compression). Couldn't comment on the likelihood of that, though. Good luck!