Hard left turns engine stumbling and throws cat system engine code

[bullseye451]

You guys know the Subarus much better than I do. I’m trying to get my 2007 Subaru Outback 2.5 non turbo running again.

1. I finally replaced my autolite plugs for NGK iridium and the engine cam to life. Unfortunately short lived because now it’s back to low power under acceleration from idle. 
2. I had replaced the Y pipe with the 2 catalytic converters and it did nothing with the autolites in it. So maybe the rear cat is bad? But I had dropped the exhaust completely with no effect.

3. I have a clicking noise under the left side of dash. It sounds like a relay being triggered every 3 seconds or so. ( It’s doing it on my other Subaru too 2006 with no check engine light on)

4. I had replaced the charcoal assembly under the left rear wheel well before and that helped resolve not being able to put gas in the tank. But it was a used assembly. I have another good used one I can put in if needed.

5. So new wires, coil, plugs, air filter, front cats, alternator / battery tests good.

thanks for your help

[1 Lucky Texan]

one very long shot - I once read of someone that had intermittent problems when turning, they found a wire harness section routed near the steering u-joint was abraded and shorting out.