My 09 Forester continues to skip although I have changed spark plugs and wires. Always reads misfire on 03 and 04. Any insight would be greatly appreciated. Thx.
How did the old plugs look?
It could be clogged fuel injectors.
Start with a bottle of Chevron Techron in the gas tank.
Use a stethoscope (or piece of hose) to listen to each injector.
Get a shop to run concentrated cleaner through the injectors.
Get a head gasket test. Do a compression test.
Along with those^ suggestions, a common things on Subies to cause intermittent misfires is grounding to the coil pack.It is situated on top of the engine, where your spark wires come out of. The ground connections consist of several bolts and they tend corrode to make bad contact.
Sometimes all you have to do is remove the bolts and clean them.
Worth a shot.