Misfire CEL

I drive a '97 Subaru Legacy Outback 2.5L DOHC. I have a recurring CEL for misfire on cylinders 2&4. If I’ve recently cleared the CEL, it will only turn back on when I’m idling. So far I’ve replaced the wires, the EGR valve and the coil. The plugs and fuel filter are only a year old. I also ran a bottle of BG fuel system cleaner through. Any ideas?

Did you test any of the parts before replacing them? Were the coils and wires good or bad? If you, of whoever is replacing the parts, isn’t testing them you may be replacing parts that still function correctly.

Last time my Subaru misfired my mechanic tested the coils, the wires, etc. All were OK. The culprit turned out to be a bad spark plug.

If you haven’t replaced the front O2 sensor you might try that. Some folks have cleared this kind of trouble by changing it.

Also, I climbed under the car and noticed I have a leaky Y pipe. Could that be the culprit?

I’m not the one replacing any of this stuff. The wires were replaced under warranty because they were tested and bad. The coils, however, no idea. I get the feeling the mechanic is just guessing about what’s wrong.

The o2 sensors were replaced about 4 months ago by an exhaust shop when I had new cats put in. I think he may have used universal, and not OEM sensors though. I’ll have to check on that.