Question

2004 Ford F150 5.4L triton with engine code P0355, change the coil pack and plugs and still showing the same thing

Answer 1

Hi there,

This code is more about a connection issue then an actual faulty coil. If you didn't use a factory coil, the issue may be a result of an aftermarket coil. If the spring inside the coil isn't making a good connection on the spark plug or in the coil you can have this type of issue.

Answer 2

P0355 FORD - Ignition Coil 'E' Primary/Secondary Circuit

Read more: https://www.autocodes.com/p0355_ford.html