5.4 3v
#4
Sounds like an issue with the transmission....how many miles? Has the fluid been changed in it on schedule? Does it only do it when hot? Don't feel bad.....I have an 05 I just got a week ago and it needs cam phaser replacements I think! yay!
#7
Then if tranny is good, I'd start w the driveshaft and go from there. Universal joints back to the rear end. Bad uv joints can cause a slipping feeling, esp. at takeoff. Hope it turns out to be simple.....uv joints are easy fix.