Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Your P0302 could be any component to do with cylinder 2.
You have swapped spark plug and leads etc.
Have you swapped the fuel injector?
Your P0204 is while injector plug 4 is disconnected, while you have the plug from cylinder 2 connected to injector 4.
Or have you swapped the injector plugs over and run the engine again?
P02xx codes are injector malfunction (o/c etc), P03xx codes are misfire related.
Have you down a compression test, with all spark plugs out?