ok i have a 2006 ford f150 with the triton 5.4 and there seems to be a huge issue and have no idea what it is. when i start driving up an incline between 40 and 60 mph it feels like the transmission is slipping but there is no lights on. i have been told it can be a bad coil pack. i think i am going to get the spark plugs change first. it does not happen every time but i just have no idea what its is i have been a ford guy my entire life and this issue and the spark plugs problem is changing my mind. if anyone know or has and clue what would be causing this please let me know