I have been trying to figure this out since I bought the truck 4 weeks. By the way I am a big ford guy. I have a 98 F150 and a 66 F100. Back to the issue. I have a 98 F150 with the 4.6l. I am getting no spark from the 1&6 cylinders. I was lacking input from the ecu. So i replaced the ECU then about 100 or so miles later the ecu is doing the same thing. The coils are also brand new. What else could be causing the problem. I have the correct power signals going into the coil but I do not have the correct pulsating ground coming from the ECU. Any help would be appreciated.