I had an inspection from the dealership since I had a misfire.
they also had compression test and all 4 cylinders at 180-200 psi as stated. I just can't believe 16 yrs old car has excellent psi however, I just planning to fix those problem by myself, do I need to get new fuel injectors? is it hard to replace them?

 

So there's something weird there: the connector for injector 1 was physically disconnected from the injector? And then they plugged it in and found it still wasn't working, and also that injector 4 wasn't working?

It seems really weird that two injectors weren't working, and also one was unplugged. I think you'll need to get some more info to determine what to do...it's unclear if the issue is really the injectors, or it's the wiring to the injectors. I would talk to whoever did the work and have them explain things because the write up doesn't make much sense to me.

You have any more info about anything that happened before you started having issues? Like, it was right after a fill up, for example (bad gas can cause injector failure)? Or any evidence of rodent damage? They like to chew on wires...