I have searched, but no how to. Even though this is change is really simple, I have seen posts asking how to do it. So here it is. Be sure to read though before starting, to make sure you have all the necessary tools to complete it.

Do not gap Iridium plugs are they come pregapped
Copper plugs need to be gapped


notes
Evo 8 2003-2004 shop manual
- spark plug gap = Stock Spark plug gap: 0.7 - 0.8 mm (0.028 - 0.031 inch)


Evo 9 and 2005 shop manual
- Stock spark plug gap 0.5 - 0.6 mm (0.020-0.024 inch)
limit 0.75mm (0.0295 inch)

Most evom users recommend 0.026 inch gap for either evo 8/9

anything above 26psi and you want to be gapped at 0.022 inch

- when tightening the spark plug use a torque of 25Nn +/- 5 or 18 FOOT-lb +/- 4
- coil packs (two black / 3 bolt pieces over 2 spark plugs) tighten to 10Nn +/- 2 or 89 INCH-lb +/- 17
- mitsubishi spark plug cover torque spec 3Nm +/- .5 or 27 INCH-lbs +/- 3
- +/- means: you can add or subtract foot or inch pounds when tighting with a torque wrench
- a spark plug socket is nice and easy(get one), but not necessary

Step 1:
disconnect battery using a 10mm wrench or socket. -always a good idea to remove power while working on the engine. plus once you are done, reconnecting the battery will reset the ecu. w/ fresh plugs in.





Step 2:
remove engine plug cover. use a phillips head screwdriver or a 10mm socket






Step 3:
remove spark plug wires and unplug wire harness - use a 10mm socket to remove the 3 screws on the plug
note: the plug wires are set in good. meaning its gonna take some effort / pull to get the wires out. dont be afraid - yank on them










after plug wire removal you can see the spark plugs set deep in the engine block




Step 4:
you will need a deep set socket with extension to reach the spark plug in its location. i used size 13/16 deep well socket to reach and unscrew the plug.







then i used this to remove the plug- not sure what the proper name of this device is, or a slang term, but works like a charm





or use a much easier tool , a 13/16 spark plug socket






Step 5:
replace your old spark plugs with new ones
i have read that its recommended to replace your iridium spark plugs every 6 months.
and change the copper plugs every 3 months

i used the cheap, but effective copper NGK BPR7ES as easy replacement for a car with less than 300whp. ie stock





Step 6:
put everything back together, reconnect battery and feel the difference. it amazes me the simple changes that you can do to this vehicle to see or feel it running better.

 

i cant beleive that your plugs looked that bad after 3500 miles. i have 10k and i am gonna change mine this weekend. thanks for the great how to. good description, and great pictures.

 

Holy rich condition batman!! You need some fuel tuning brotha. There is no way plugs should look like that after 3500 miles.

And changing plugs every 6 months is just crazy, my car has 40k modded miles and my stock plugs still look new.

 

The spark plugs on my old ford explorer didn't look that bad after I put 40k miles on it, and plus however many miles the previous owner put on them.

 

wow, new plugs at 3k?

stock are Iridium and suppose to last a lot longer.

any noticable gains w/ NGK coppertips? gapping require?

 

The stockers are suppose to last 60,000 miles.

 

Do yourself a favor and get a spark plug socket. Not that you can't use your little grappler, but it'll be easier with a spark plug socket.

Also you forgot to mention the amount of torque to tighten the spark plugs and check the gap. Yes they come pre-gapped, but every once in a while, the gap is off for one reason or another.

 

sorry posted wrong pic - those were the plugs after 200 miles of ses light safe mode

 

other pictures of the condition of my spark plugs - before the change
https://www.evolutionm.net/forums/sh...d.php?t=115144

 

I checked my plugs at 10,000 and they looked perfect. I can not imagine replacing them at six months unless you race.

 

no gapping required , i noticed a better acceleration. its not much, but the car responds better than my original fouled ones.

 

that sounds like a good idea.

if you want to check gap. anything between .028 - .031 will work.

if you want to torque your plugs (recommended) 25 nm or 18 ft-lb

 

this pic is with the engine running in safe mode for 200 miles. rich is right , i was getting 5 mpg!

 

Is anti-sieze compound on the plug threads not recommended on the evo?

 

thanks for the quick write up man ive been meaning to do mine but i havent got around it yet