xbl1nd

I have an interesting scenario with my car.
I run STI 550cc injectors on my KA, One of them which keeps on leaking

I have replaced the injector O ring (Large and smaller one) 3 times now and it still leaks...

I am testing by pulling the fuel rail out and turning the Key to ACC...I have replaced the injectors in my other 3 and have had no problem...for some reason this one is giving me a headache..

Any particular reason an injector would still leak even with new o-rings? (NISSAN OEM KA/SR injector orings which fit the sti injectors)

Is this a symptom of a bad injector? I would hate for that to be the case since its impossible to buy just 1 Injector (sti 550 atleast)

if any one has any other test I should try or any insight please share...Also if anyone has a spare sti injectors or a decent place to have mine serviced, please share, thanks