Ok, I'm going to assume this is a CIS-E 102 engine. Remove the 5mm hold down bolt and swap the injector from one cly to another, if the skip moves, theres your problem, if it doesn't. Run compression and leakdown. The seals are nothing but odd shaped orings so the injector will wiggle and spin and such.
I also am assuming you checked for vacuum leaks and so as well.
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