Auto Mechanics Question

[Hawkez]

I consider myself to be moderately mechanically inclined. I changed a fuel injector last week on my '97 Cavalier and now I am having a few problems. The initial problem was a fuel leak around the injector. I changed it and the leak has not come back, but the car idle very rough. It seems to drive fine at higher RPMs. The check engine light came on and I had the code read and it points to the number 4 cylinder misfiring. That is the injector I changed. My question is, is there special procedures to installing fuel injectors? Was I supposed to use a special chemical to clean or lube the injector? I coated the o-rings with a thin coat of motor oil, but that is it. I tried to be careful installing the injector and I thought it went in rather well. OR, does my problem sound like I simply bought a faulty injector?

Any help would be appreciated.

Thanks,
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