^exactly do a compression test first to see if your cyl isnt toast. After that if you have good comp, spark and fuel then my next step would be switching the wiring harness. I have had a similar problem before. I actually cut the wires to the injector then jumped it over with the 3cyl so it would shoot fuel at the same time and it ran great till I bought another harness. This has actually happened to me twice with the ek civic.