Auto Zone will rear your computer codes for FREE. If you have any bad coil packs they will tell you .
A bad coil can damage a converter. If the engine is misfiring, it will cause raw fuel to get into the converter and that can cause failure.
Remove engine cover, determine which coil is bad or better yet replace them all. Remove the electrical connection from ignition coil, remove 7/32 bolt from coil (be careful not to drop),pull coil from top of sparkplug and remove.
Go to AutoZone have them rear your codes for FREE. This way you will know which Coil Pack is goig bad / or is bad. If you have a 4.6L you will have only 2 Big Coil Packs. If you have the 5.4L you will have 8 Coil Packs , One coil pack for each cylinder.
Ignition coil no 7 primary circuit fault, if your expedition has COP (coil on plug) then the second from the back on the driver's side plug wire needs replaced. If you have coil packs(2 of them) then the coil which connects to that spark plug wire is probably bad
You may have a bad coil I had moisture some how get in and short out the plug coil.
Auto Zone will check your codes for FREE... It will also tell you which one is bad.
Auto Zone will check your computer codes for FREE... Have them pull your codes and go from there. I believe you have a bad coil, or coil pack.
Have AutoZone check for codes (FREE). It may be a bad coil pack...
Could be a bad ignition coil each cylinder has its own
Bad coil pack or spark plugs...
Engine misfire. Possibly a bad coil or spark plug.