ChiefBlue

I have a 2008 F150 XL 4.2, I got a check engine light and rough running truck all of a sudden. Error Code for #3 cycle plug. Replaced plug still running rough but no check engine light. Truck knocks,

techrep

iTrader: (1)

Try the coil on #3 or if you want to troubleshoot , swap a coil and see if the code follows.

nrivera04

Correct me if I'm wrong, but doesn't the 4.2 have a single coil w/plug wires? If you've only changed the plug, it could be a bad wire.

ChiefBlue

Alright, I appreciate the information. The 4.2L has a coil pack, is there a way to test the coil pack ? Also, I replace plugs and wires today idle is smooth in park but in Reverse or Drive the truck bogs down and runs poorly. Shaking when taking on the gas to speed up. I am lost

BadFish523

As stated swap the coil to a different plug and see if the error code follows to the new plug or stays on the same plug. That can tell you if its the coil or something else specific to that cylinder.

nrivera04

You cannot swap coils around on a 4.2 - It is a single coil with plug wires.

BadFish523

Ahh sorry bad advice.

nrivera04

See if this link will help
http://easyautodiagnostics.com/ford/...he-coil-pack-1

ChiefBlue

I truly appreciate all the feedback for all of you. I did plugs and wires first nothing changed, I replaced the coil pack problem solved. So my 2008 with 175k miles on it is running good.

odcdrummer