Generally P0305 will be a cylinder 5 misfire. It's triggered by the crank position sensor picking up that the crank isn't rotated as rapidly by firing cylinder 5. The reason for the long list is that it could be caused (or misdiagnosed) by a number of factors: a spark plug may not be firing correctly because it's old or fouled, because its coil is failing or not being triggered (bad ground or wire), or because an injector isn't supplying fuel. You could also have a mechanical problem - leaking valve, broken piston ring etc. You could also have a crank sensor which is picking up an anomaly which isn't really there.
Usually you would start with spark plugs and coils - they should all be the same. Swap the coil from cylinder 5 and any other, and see if the error changes to P030* where * is the cylinder you swapped with. If that doesn't change anything, swap the spark plug and see if that changes anything. Spark Plugs and coils supposedly should be the most common issues, although my luck has seen sticky fuel injectors causing similar problems on the 5 cylinder cars.