Triple Gran Cherokee on 1999 ignition coil

That such a good day, I have problems with my Grand Cherokee Laredo 1999 truck with a 4.0 -cylinder engine online., The problem is that it is pulling, it trembles a lot, this went to root that I change bujias, this engine model does not bring wiring to the spark plug Sparking, as if I were short of the coil, but I already revicts and clean and assure me that everything is perfectly well connected and still sparkled the spark plug, my doubt is whether the coil already valuits or may not be the appropriate ones or you want an independent short and I am impacting it on the ignition system ... help by favo if anyone knows about this, ...