Bought a small project 2011 CBF for my son. Upon collecting and riding back, the engine started to misfire and cut after hard throttles and hills with the engine warning light activated. After a short rest she was off again until the next hill. From cold, it takes 2-3 goes to get started, rough idles thereafter while also having a deep 2 second bog. As mentioned, it's a 2011 and done a solid 20k mileage.
I originally put this down to the infamous CBF fuel pump.
I have replaced;
Fuel Pump with another from a breakers (regretting since I'm now doubting the quality)
Plug,
Air filter,
Drained the tank since the fuel cap drain was blocked and water had gathered (also ran a bit of Wynn's through JIC).
Have removed and cleaned:
Fuel line,
Fuel injector,
& IAC valve,
Am also running Redex in the fuel.
Throttle cable is sound.
What are the next best logical moves? Replace the IAC valve with new?
Wisdom gratefully received!!