2004 Ranger, 3.0 engine. Above codes are misfire 1st 1,000 rpm and misfire on #6.
Drives fine, but idles a little rough. Prolonged idle causes very rough idle, almost unable to drive. Turn off engine and restart, it runs fine. This makes me think its not mechanical, but electrical or fuel related.

Replaced plugs, wires, air and fuel filter, and inspected/tested coil pack. Reset codes and swapped #2 and #6 at coil pack. Engine ran fine, after a day or so, check engine light came on...misfire still says #6.

Could this be the fuel injector? I've ran Seafoam through the system, but it didn't help.

 

Get a plug wire puller tool --- With engine at idle pull the #6 wire and see if spark is jumping to plug.......... no spark ..wire or coil pack.... spark! injector problem, if it is injector you can try Chevron with Techron or the lucas fi cleaner first

 

It has a spark...although without a proper meter it may be weak or intermittent. Put Seafoam in to see if this fixes it. Reset the fault codes and will have to wait to see if check engine light comes back.

Murphys Law holds true if it's the injector; the #6 is the hardest one to get to!