hey guys i have a 94 sentra 1.6L and i think that one of my fuel injectors is bad, the car was running really rough, so i pulled each plug wire one at a time while the car was running and every time i pulled a wire the engine bogged down and almost stalled, except for when i pulled the plug on the # 4 cylinder, then there was no change in the way the engine was running. so then i pulled the spark plug out to make sure that it was getting spark and it's got plenty of spark. so next i pulled all the wires off and tried to start it with the throttle wide open. then i pulled all four plugs and the #4 plug was completely dry while the rest were soaked. so i'm guessing it's got to be an injector problem. could it be anything else? and how hard are they to change?