300 miles on rebuild and won't start, I'm out of ideas

I have ~300 miles on a JDM rebuilt engine. At the time of the replacement I replaced all the plugs/coils/wires. It ran great for the first 290 miles or so but then I went to town to run errands and after one stop I had a very hard time starting and it didn't want to idle any more. I limped home to diagnose. Upon opening the hood I could smell a bit of fuel. It seemed that one of the injectors might be leaking so I went ahead and replaced the O-rings on those. Turns out one did have some physical damage to it and was probably the culprit. After this went through a deflood procedure and still had no luck getting it to start. It seemed like it was having a harder time starting than before I changed the o rings. I've triple checked all the vacuum lines and everything seems good. I'm all out of ideas of what else to even check. Any help would be appreciated.



-MT