How do you replace an ignition coil in a 2003 F150?

Answer 1

These trucks have electronically controlled ignition, and use a distributorless ignition system. You won't find the old-style can-shaped coil on them! They have a rectangular "coil pack" that is mounted on the top rear of the engine, and is pretty straightforward to replace. Just tag all the wires so you can make sure you put them back where they belong (I strongly recommend you take a picture for reference!), disconnect the connector from the PCM, remove the bolt (7mm, I think) that holds the coil pack in place. You might have to take some fuel rail support brackets loose to get the pack out. Once it's out, put the new one in place, replace all the hardware you took loose, then replace the connector and wires in their original locations. Make sure you get the ignition leads back in the proper order!

On the other hand, you may instead have a separate small coil over each spark plug. If this is the case, simply remove the small (8mm) bolt that holds it in place, slide it off, and slide the new one on. I strongly recommend that if you replace one, you replace them all.