Fuel Injector installation problems

[kujio]

I recently bought a Niehoff fuel injector and an o-ring set for my 91 240sx (KA24DE). I replaced the fuel injector and kind of guessed were the o-rings went without really knowing. The car ran fine for about 3 days but now its doing the exact same thing as it was before I installed the new injector. Is it possible that I installed the o-rings wrong, or is it a problem other than the injector?

[s13sr20chris]

if its a misfire or a fuel leak then yes otherwise no.