Cylinders 3 and 4 not firing
Pull back 3 plug wires and engine idle does not change.
Swapped Plugs, Plug wires, Injectors.
Replaced Coil and ECU.
When it was misfiring on one cyclinder a ECU reset fixed it for a little while.
Have you checked the coil? Subaru's are VERY common for head gaskets leaking, you may have coolant or oil leaking into your cylinders. When you replace spark plug they're dry, so your car may drive ok for a few weeks until the leak dampens the plugs. Take a look.
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