Have a early 99 450 sd. Surges at idle enough to stall out. Sometimes if I play with the throttle it will smooth out for a few minutes then start again. I have replaced the icp censor twice just in case the first one was bad. Replaced the ipr. Replaced the cps. Dropped the tank cleaned the filters. Replaced the fuel pump. Replaced the ebp tube. New oil motorcraft. Truck ran good befor it started never even had to plug it in during winter. I checked as many wires as I could. Did not find any bare spots. When the truck starts it will sometimes die at the bottom end of the surge. While it is running if I trip the fuel cut off it stops surging and ideals like normal for a wile. Bought a bidirectional scan tool. Dose not work I'm assuming because there is only 7 pins. What would be making my truck do this.