1.2 petrol problems

[3potpolo]

Hey so I bought this car last December and it had a misfire on cylinder 2 so me and my dad changed the timing chain and the guides the problem is happening we have changed the spark plugs and got a new battery and the problems is still happening today I had a look at the ignition coils using a multimeter and they seemed fine. So the problem is it has a rough idle and its over fueling we have thought that it could be a clogged cat, an injector or the PCV valve is blocked we did check the PCV valve and shook it it did not make any ticking sounds so that may need replacing but i just need some guidance as i don't want to keep spending money on parts and realize that it did not fix the issue.

please help me lol