Replacing Spark Plugs on a 2004 V6 3.9L Mustang - Ford Mustang Forum
 
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post #1 of 12 (permalink) Old 08-18-2009 Thread Starter
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Replacing Spark Plugs on a 2004 V6 3.9L Mustang

Hey guys... I know this has probably been posted somewhere but I figure why not ask here. Repair shops want like $100+ to replace spark plugs... Knowing me, I'd rather learn how to do it myself than pay someone else that kind of money. So if anyone can write down some easy to follow but detailed steps I would really appreciate it. Holla
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post #2 of 12 (permalink) Old 08-18-2009
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Replace Spark Plugs on a 2004 v6 mustang

hi, well I replaced my spark plugs each one cost $10 (NGK IRIDIUM SPARKPLUG) are the best est add on 7hp. I have a 99 gt so I ended up spending around $87 with taxes. installing them yourself well you dont have to. I took my car to a shop a group of guys had a smirk on their faces & charged me $90 to install them, so i smirked back & left, i found an independant mechanic that had nothing to do with a shop & he charged me $20 for the installation it was worth every dollar, I feel the difference but it all depends also what spark plugs you get, I chose NGK IRIDIUM well worth the bang for the buck. let me know how it goes, good luck.
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post #3 of 12 (permalink) Old 08-18-2009 Thread Starter
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spark plugs will give you extra horsepower? or just give you back lost horse power? Also, I bought some autolite platinums not the cheapest ones but not the most expensive. I don't think you understood me but I'm wanting to do this myself so I don't have to pay ANY money to a mechanic to do it and so I can learn how to do it in the future
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post #4 of 12 (permalink) Old 08-18-2009
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no spark plugs no matter how advanced they say they are will not add horsepower.. ive never exactly changed spark plugs so i cant give you a detailed step by step but.. i dont really think theres much to it.. just make sure you keep track of what wire goes to what plug lol otherwise your car wont run very well lol

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Best 1/4 time: 15.036 @90.92mph, 2.148 60'
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post #5 of 12 (permalink) Old 08-18-2009
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ok, i'm not great with directions but here we go. grab the spark plug wire by the boot, or where it connects to the spark plug, and gently pull, twist, and wiggle slightly until it pops off. grab a 3/8 ratchet, an extension if you need more clearance, and a 13/16 spark plug socket. be sure to use a "spark plug" socket, it has rubber in it to prevent you from breaking the fragile plug. unbolt the plug from the block. grab the new plug and put a little bit of anti-seize on the threads. start screwing it in by hand, then use the ratchet to "snug" it down, only snug, too tight can damage the threads and cause you to lose compression. put a little dielectric grease in the boot and pop it back on. repeat 5 more times. removing the air intake may be necessary.
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post #6 of 12 (permalink) Old 08-18-2009
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Read this thuroughly before attempting, and during if you need a reminder.

DO THIS WITH A COLD ENGINE!
You will need a basic tool kit with 3/8 in. bits and a 3/8 in. ratchet with two 4 in. extensions, and also a flathead screw driver to remove your air intake housing. Make sure your new plugs are properly gapped. Make sure you have a bit to fit the new plugs, it will also be used to extract the old ones. I would not recommend new wires unless your old ones are shot or you are upgrading to a performance wireset. Now...

Lift the hood. Remove your air intake. This inludes the filter, MAF sensor, and all plastic bits up to the throttle body. Look on the side of the engine, just below the valve cover. There are three thick, likely black, wires running to the cylinder head. They are evenly spaced and have thicker "boots" where the wire meets the head. Pull on one of those boots, but ONLY ON THE THICK BOOT. Do NOT pull on the thinner wire part. You could break the wire if you tug on anything but the boot. Give it a good tug and it should come right off.

The plug is now exposed. Take your wrench, with the proper bit and number of extensions, and (lefty-loosy, righty-tighty) Take that old plug out. If it's stuck use some WD-40. Don't risk damaging your cylinder head in a "world's strongest man competition" with these things. Inspect the plug and compare it to the new ones. Cool, huh? Look for a chart on google images(search for "spark plug chart") and compare this plug to what plugs normally look like under certain conditions. When you're done, assuming there are no problems, tighten in a new plug (a little more than hand tight, but don't force it too much) and push that wire back on. It's that simple.

Also: Replace the plugs one at a time! If you take all of the wires off and then pull all of the plugs, you'll have a total disaster when trying to rewire.

Most of the plugs are simple to remove. A few are very, very tricky. At times it will seem hopeless, and you will feel like saying, "Screw this crap! It's worth $100!!!" But it simply isn't. The more you do things such as this the better you will become and the more naturally it will come to you.

When you're done, bump the engine over a few times. This means: crank it, but don't let it start. If it sounds normal, start it and wait a few seconds. If anything is a miss, shut it off quickly so it doesn't get too hot. Recheck all of your wires and make sure they're pushed tightly on there.

It should start without any issues, given you followed the directions well. Given this is the case, go for a well-deserved ride!
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post #7 of 12 (permalink) Old 08-19-2009 Thread Starter
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are those directions for a 2004 v6 mustang or just any car... because i dont think i have to take off my CAI to get to my spark plugs... there sitting on the right of the engine bundled together am i right?
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post #8 of 12 (permalink) Old 08-19-2009
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Quote:
Originally Posted by andybz View Post
are those directions for a 2004 v6 mustang or just any car... because i dont think i have to take off my CAI to get to my spark plugs... there sitting on the right of the engine bundled together am i right?
???

are you sure you know where your spark plugs are?

you will need to remove your cai to replace the plugs on the passenger side.

-2000 3.8L TKO600, 1.8 60ft, 8.71 @ 81mph
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post #9 of 12 (permalink) Old 08-19-2009
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Quote:
Originally Posted by andybz View Post
are those directions for a 2004 v6 mustang or just any car... because i dont think i have to take off my CAI to get to my spark plugs... there sitting on the right of the engine bundled together am i right?
You're kidding, yes?

You have a V6. 6 cylinders in a V assortment, with 3 on each of 2 sides, coming to one point at the crankshaft. You have 1 spark plug per cylinder. 3 Plugs per side. You have to take the intake off to access the left 3...

If you can't figure this out, you need to have someone else do it.
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i changed my plugs in 30 minutes and never had to take off my CAI. i got some bloody knuckles tho. and Andybz, your gonna want to follow the wires that come off of that bundle to the side of your engine block to find your spark plugs

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post #11 of 12 (permalink) Old 08-19-2009 Thread Starter
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lol my bad i was thinking of something else
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Quote:
Originally Posted by MattLopez15 View Post
i changed my plugs in 30 minutes and never had to take off my CAI. i got some bloody knuckles tho. and Andybz, your gonna want to follow the wires that come off of that bundle to the side of your engine block to find your spark plugs
well it can be done that way, if you dont mind fighting and struggling every step of the way. it takes all of 60 seconds to remove your cai, and then you have room to work.

-2000 3.8L TKO600, 1.8 60ft, 8.71 @ 81mph
-1988 Jeep XJ, bone stock 2wd
-1994 Jeep XJ 4wd, 3" lift, 31" tires.. rust in peace..
-1997 Jeep XJ 4wd, 7" lift, 35" tires, front/rear lockers

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