Maybe a compression check or borescope inside the cylinder to check for carbon build-up affecting the compression?

I own a 2011 clubman s, driving to work i pull a hill about a mile and a half, mile up the hill the engine light comes on, obd code reads misfire, i think its the timing chain. in sport mode normal, no code. why? have changed coils and plugs. had a walnut blast head cleaning and injectors replaced. no changes. engine code comes up misfire. can i try anything else?