Losing power when going up hills, check engine light comes on and misfire on cylinder 1 & 2, catalytic converter code comes on too, I'm wondering what is causing the loss of power?

Stopped up cat will cause lose of power. But if it's the 2.2L or the 2.5L both plugs 1 & 2 come off of the same coil. You could have a bad coil or a fouled spark plug. Sometimes one fouled/bad spark plug will cause both plugs on one coil not to fire. This will also cause a lose of power. I feel that a coil or spark plug issue is more than likely your issue.

Thanks for responding. I have already replaced spark plugs and ignition coil, but that didn't affect it. I've had this error code come up sporadically about the exhaust, code 420, and now the misfiring under load. Am wondering if misfiring and a failing exhaust system are connected? Would a bad cat converter contribute to misfiring, or does a misfiring issue cause a cat converter to fail?

My check engine light has never gone of since I bought my subaru BH5 neither is the power light. .dunno what the problem is. .

@Laichena I plug in the diagnosis and give out the cord, you get

Thank you so much. .will first do the service which I not done for long

How long can a turbo engine last?

Just been to a mechanic he asked me to do service

My 2004 outback has had the check engine light on for 9 years off and on, dealer did nothing. We've changed all the sparks several times, changed the coil pack, the wires, last changed oxygen sensor. Stalling on hills, flashing check engine. I'd love to get a few more years out of the car, but I can't trust it. I'm not sure I'd ever consider buying another Subaru.

I had the same issue. A chipmunk got into my fuel line. Changed it out and it started stalling around sharp corners and hills. Turns out I disrupted the fuel filter when I changed the fuel line. I was mind boggling for about a week cause the car ran perfect before I change that fuel line. I ended up changing the filter week later solve the problem

I have traced my severe power loss to a clogged cat. My 09 Legacy ran for 2 years on an aftermarket cat from Eastern Catalytic. Despite the power loss, it did not throw any codes. After replacing, Plugs, wires, in tank fuel filter (PIA), injectors, it still wouldn't go over 60mph and MPG dropped from 30 to 20. I replaced the OEM cat a couple years ago but never threw it out. After reinstalling the OEM cat, the car ran normally.