Head Gasket's, Coil Pack or Trans?

[dorelse]

2003, 106k Miles, NA & Auto

So...the Baja is not healthy. Started middle of last week and I can't seem to isolate it...it seems to 'miss' when running, and I get figure out if that's really a transmission slip, or a misfire condition caused by leaking head gasket?

I changed the transmission fluid & filter (oil fluid was old, but otherwise ok, no metal chunks or otherwise signs of an issue. Smelled fine too.) No change in how the Baja's running.

I have no overheating issues, nor any contamination in the engine oil...its a fresh change from a few weeks ago, and it looks to be at the same level and I'm not noticing any signs of contamination.

Antifreeze looks fine, but I can't be 100% certain since I don't know its age. Timing Belt change is forthcoming, so would be flushing at that time. I have noticed an antifreeze smell though when I'm done running the car, which is why I was thinking head gaskets?

Any thoughts or advice would be appreciated. Since the head gaskets need to be done eventually anyway, I'm ok with that honestly. I plan to bring it to our local Subie specialty shop today for an evaluation.

[dorelse]

Definitely have this narrowed down to a 'miss' in the engine. Planning on buying a coil pack and just swapping until I find the culprit.

If a head gasket were leaking, could that cause the same condition?

[Acro2pilot]

Very hard to say just from a post but bad coil packs at this age and mileage are very likely. I am sure I recently posted the pics of mine showing the part numbers and all that. If you are getting a missfire code on X cylinder you can swap in the new coil and see what happens, or before you order coils you can swap X for X and see if the fault travels. Mine were fine until about 17 psi of boost and then they showed their age, 4 new coils made it all as it should be. Also be sure to check the condition of the coil pack connectors, they can fail as well.

[dorelse]

The problem is that I have no misfire codes or trouble codes...at all. I definitely have some type of misfire...since mine's a NA, I was going to swap in a new coil pack (since all 4 are together in 1 unit) and see if that works. I'm thinking it will after some more investigation last night.

Thanks for your thoughts...I just would have expected a code from a misfire...

[Acro2pilot]

For some reason I thought you had individual coil packs and not the single all in one, my bad. I have had experience with those and they have a few problem spots. On my 99 RS (same pack) I installed new plug wires in the fall one year and by spring they were corroded and missfiring. I would replace the wires before the coil, they can easily go bad, they can corrode or look healthy and still be bad. The connector to the coil pack can get corroded as well. You can clean out the brass connections on the plug with a bore brush if those look bad.

As I recall the plug wire issues on my RS did not throw a missfire code.

[dorelse]

Root cause ended up being my oil soaked plug wires...they were also corroded terribly where they connected to the coil pack, and my tube seals are in need of replacement (and then valve cover gaskets as well).

I've already spent the money on a replacement coil pack so I'm going to just keep the stock one as a good spare for now.

I'll get it fixed up this weekend.

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