I have a 2001 SuperCrew with a 5.4. I have replaced an Ignition Coil in February and again last week. Today it started shaking like I had a bad coil again. My shop replaced the #4 coil last week and he said it was the #3 in February. What is causing them to go out and what can I do to prevent this in the future. Also if it is the #3 or #4 coil again, is there something specfic that I can do to prevent those from going out again. Thanks for your input.-LouScrew

 

Check for a leaking coolant line. It runs directly overhead of the #3 or #4 coils.

Steve