Hey guys!
Great forum you got here and hopefully I can get a little help. I have a 2003 Ranger 3.0L 2WD that recently had its check engine light come on. Autozone said misfire on cylinder 3 and missing on 3 during start up. I bought new wires and plugs and was wondering if someone could point me to a specific instructions for how to replace my spark plugs? And the wires? Any special tools I would need for the job? Sorry if these are dumb questions just not super truck knowledgeable

 

Just get a spark plug socket that fits your new plugs, and replace them one at a time in tandem with the wires. Do not disconnect more than one wire at a time unless you have a firing order diagram. It's easiest to pull the wire, match it to the same length new wire, install the new plug and reconnect the new wire to the plug and coil pack. Pretty simple installation and lots of info online. Welcome to the forum!

 

^^ +1

Most spark plugs come with the correct gap between center electrode and ground electrode, key word is "most"

Rangers tend to eat non-motorcraft spark plugs, so if possible get Motorcraft plugs

Also I put a can of Seafoam gas treatment in the tank once a year, $7-$10, it keeps my 4.0l's injectors clean.
I used to say BS on gas treatment(pre-fuel injection days).......until I started getting missing, random though not specific to a cylinder, for what it's worth my first can cleared it up, that was after me spending $$ on new plugs and wires that were less than a year old, lol.
315k miles on the original injectors now

You probably need the new plugs, wires are up to you, but don't forget the injectors, in your engine the injectors are sequential(only the cylinder with open intake valve is gets fuel), so dirty injector can cause a cylinder specific miss.


And for a bit of bad news.........I think the 2003 3.0l was on the list(TSB) for bad valve seats in the head, they would come loose and float causing a steady miss but it would come and go, I think it was the exhaust valves that were effected.