Nissan Repair: 94 Sentra misfiring, gas mileage, sentra

Question
My Sentra is misfiring on one cylinder. Replaced cap, rotor and plugs. It is only one cylinder, the rest of the plugs are clean. The misfiring cylinder is black with carbon. Gas mileage is teeerrrible. I noticed that inside the dist. cap was a little oily? It seems to be dry now that I cleaned it. Could it be the Distributor itself? I am a mechanical guy, but this is " wrenching " on me. Need help Please?

Answer
David,

You may be approaching this from the wrong end.  I would check the injector for that cylinder and see if it is stuck.  If it is open and running too rich it will cause the problem.  I have seen this too many times before.  I would change that injector and your problem will probably go away.  Email me back with what you find.