Ford Repair: ford explorer 99, ford explorer xlt, luck chris

Question
ford explorer xlt 89000 miles, very rough idling and when start driving it; ok when driving above 45 mph it's been diagnosed: misfire in 5 cylinder code, (spark plugs, wiring, gas filter, complete tune up has been done, any suggestions? thanks

Answer
Hi Gerome thanks for asking and sorry about the delay.
there are a couple things that I wouls first check. I would have a compression test done first that will tell you if there are any mechanical problems. If this passes sheck the spark going to that cylinder if that is ok then there is only one other thing it can be--- the fuel injector. if it is stuck closed then no fuel will go to that cylinder but it will tend to clear up at higher speed, same if the injector was stuck open, if there is to much fuel going into the cylinder it will misfire at lower rpms and smooth out at higher rmps. Have that injector check with a NOED light to see if there is a pulse if there is then try sweapping the injector with another one, if the misfire changes cylinder then it is faulty and needs replacement.
good luck
Chris P