Hello I am new to this site, I have a 2008 ford ranger sport 4.0 V6 for a few months now I've had a misfire in my 5th cylinder, I've already changed out my spark plugs and fuel filter and it keeps coming back any help would be great!

 

Welcome to the forum.

What did the old #5 spark plug look like?

3 things are needed for a cylinder to fire
Spark, at the right time
Air/Fuel mix, in the correct ratio
Compression

Compression is a mechanical function, and while not likely the problem, you can test it and take it off the table, so just spark and fuel are left.

Spark has 3 parts, Coil, Spark plug wire, and spark plug.
On your engine #1 and #5 share the same coil, and if you are only getting P0305 code then coil is "probably" not the issue.

But you can also take that off the table if you swap #1 and #5 wires at the Coil.
1 and 5 will be right next to each other, just swap them around, and drive engine that way, if you lose P0305 and get P0301 then coil pack is bad.

Spark plug wires can be tested with an OHM meter, but you can always swap #5 and #4 or #6, which ever is long enough, and again see if code changes, P030X


Air/Fuel is harder to check, so last
Can you feel the misfire all the time or does it come and go?
And when does it come and when does it go?

I.E. cold engine, warm engine, idling or higher RPMs, accelerating only

 

Thank you for that I will check those once I have a day off to do so, and I never feel the misfire after changing the spark plugs and fuel filter the engine runs a hell of a lot better then before, I get to speed faster and just overall runs great I had a thought could it be a bad sensor?

Also it's at driving speed, it's been after a bit of driving but not right away I'd say just before driving temperature