Some history.... I have a 1998 F-150 with the 5.4L. About a year ago,I blew a spark plug outta the head, drilled and tapped the head and put a heli coil in. So, every time I replace the plug, I have to replace the heli coil as well.
Current problem... My truck every now and again will stutter when I am driving it. I thought it was the spark & heli, so I replaced them. OK, not the problem. It happens when I am running up my RPM's around 2500, or when I am going down a hill, when it kicks it will sometimes bucks 3-4 times. My RPM's though, they do not move when such is happening, so I conclude it isnt a tranny problem.
Is it anything to do with the overdrive? Tries to kick into overdrive, but cant??
Does anyone have any idea??