Want to replace spark plugs on '05 GT.... should I really be scared?

Ok, I've heard a few horror stories about I guess its the head design on the '05, something about the plugs breaking when you try to remove them. I'm by no means a great mechanic but I've never had a car that I had to pay someone to do something as simple as replacing the spark plugs. I bought the car used a few months ago. It has about 43k miles on it. I'm pretty sure they are the original plugs and after what I've been told I'm a little hesitant to do this myself. It is my daily driver so if I'm stuck having to take the heads off to be repaired I'm screwed. My fellow Bold Moves peps I need some advice. Have you guys experienced problems with this? How wide spread is this with the '05? I've got a shop close to my house that I trust and I'll take it to them if I have to but for the time and convenience factor I'd rather just do it myself.

It's the 2 part plug design.I talked to ford and it is more common on the trucks.It is something that can happen,and can be repaired without pulling the head.I'm sure american autosports can help you out.I would think the plugs would be good for 100k.

I've replaced mine with a one-piece plug, but my engine had only 12K miles on it at the time. I recommend replacing yours ASAP; these are poorly-designed plugs in these engines and no way I'd let the factory two-piece plugs sit in there for 100K. I had no problem removing mine, but they make a horrible grinding sound as you remove them - that was unnerving. Put nickel anti-seize on the threads of the new plugs before installing them. There's a TSB on removing/replacing these plugs somewhere out there on the internet; I'll look for it when I get the chance - it's a pretty good guide for R&R.

**Edit** - here's a thread with a bunch of useful info, including the TSB: http://www.fnsweet.com/forums/05-09-roush-mustangs/44003-ford-spark-plug-tsb.html

Maybe David M. Could chime in as well. I believe he just replaced his as well a few weeks ago. He has around 50k on the motor.

I too am thinking about replacing mine. Let me know how it goes

Thanks guys! I followed the links you guys posted and found Ford's TSB. I appreciate the info! I'll let you know how it goes.

I just changed mine a few weeks ago. It was a bit scary. I warmed the engine up to normal operating temperature then removed the coil on plugs, I then sprayed a good penetrating oil down into the spark plug hole until it just covered the top of the plug wrench head, I let it soak for about 45 minutes. After the soak I used a normal socket to break the plugs loose only with about an 1/8 turn. I then let it soak an additional 15 minutes then began the removal process. I will warn you that it will creak and pop while you start removing the plugs. I went real slow and used a 3/8 socket wrench so that I couldn't apply too much torque on the plugs as to break them. Be sure to apply a good nickle anti seize on the neck of the new plugs before installation. If you feel like you aren't up to the task let me know and we'll try to figure somthing out to help ya.

I might need that help David...

Did you feel any difference in performance? I know you were losing a little on the top end

It smoothed things out quite a bit. After inspecting my old plugs and comparing them to the new ones the electrode had burned down to the point that my gap was about twice as large as it should have been. Funny thing was that the problem I was having at the track turned out to be my fuel cutoff switch. It seems that it was hanging partially open and not allowing propper voltage to the fuel pump resulting in the cutting out I was experiencing at full throttle. Its an odd problem that I don't think I have ever heard of happening before but after resetting the switch it runs like it used too. Ive had problems with my fuel cutoff before. I've gone out twice on different occasions and could not get my car to start due to the fuel cutoff switch being tripped for no apparant reason? Reset and started right up. I guess its faulty somehow???? Greg have you ever heard of this happening? Also I wonder if this is a warranty item even if your out of warranty? Im guessing it needs to be replaced.

hmmmm should I check my fuel cut off...I have seen some drop off at the upper RPMs.

Possibly could be my imagination

When mine was acting up it was like I was hitting the rev limiter as soon as I went to WOT. My best guess is like I said before that the fuel cutoff somehow was limiting voltage to the fuel pump and therefore starving my motor of the precious fuel it needed to perform at the level that it was before.

DBLDARE wrote:It smoothed things out quite a bit. After inspecting my old plugs and comparing them to the new ones the electrode had burned down to the point that my gap was about twice as large as it should have been. Funny thing was that the problem I was having at the track turned out to be my fuel cutoff switch. It seems that it was hanging partially open and not allowing propper voltage to the fuel pump resulting in the cutting out I was experiencing at full throttle. Its an odd problem that I don't think I have ever heard of happening before but after resetting the switch it runs like it used too. Ive had problems with my fuel cutoff before. I've gone out twice on different occasions and could not get my car to start due to the fuel cutoff switch being tripped for no apparant reason? Reset and started right up. I guess its faulty somehow???? Greg have you ever heard of this happening? Also I wonder if this is a warranty item even if your out of warranty? Im guessing it needs to be replaced.

I havnt seen that they usually get triped and shut the pump off. What probablly happened is the plugs were so worn that it screwed with your fuel trims and then it relearned after the plug change and now she runs great. But anything is possible. When the plugs go bad these cars do not like to run on the top end. I have switched to a 1 piece Brisk silver electrode 2 steps colder than stock and these plugs use a conventional plug gapper.

If they break I have the remover I have never used it but thought I would get it just in case

KBCal wrote:

DBLDARE wrote:It smoothed things out quite a bit. After inspecting my old plugs and comparing them to the new ones the electrode had burned down to the point that my gap was about twice as large as it should have been. Funny thing was that the problem I was having at the track turned out to be my fuel cutoff switch. It seems that it was hanging partially open and not allowing propper voltage to the fuel pump resulting in the cutting out I was experiencing at full throttle. Its an odd problem that I don't think I have ever heard of happening before but after resetting the switch it runs like it used too. Ive had problems with my fuel cutoff before. I've gone out twice on different occasions and could not get my car to start due to the fuel cutoff switch being tripped for no apparant reason? Reset and started right up. I guess its faulty somehow???? Greg have you ever heard of this happening? Also I wonder if this is a warranty item even if your out of warranty? Im guessing it needs to be replaced.

I havnt seen that they usually get triped and shut the pump off. What probablly happened is the plugs were so worn that it screwed with your fuel trims and then it relearned after the plug change and now she runs great. But anything is possible. When the plugs go bad these cars do not like to run on the top end. I have switched to a 1 piece Brisk silver electrode 2 steps colder than stock and these plugs use a conventional plug gapper.

Could be. I hope thats the issue as I can't see how the fuel cutoff would act up like that but like you said anything is possible?

Good to know you have the removal tool if its ever needed. Knock on wood!

Your awesome Greg!! I didnt know you had the removal tool. Makes me feel better if for some I run into any issues.

Hows your car running by the way? Ready for Mods Vs Rods?

Im almost ready but I will be ready Im going to do everything I can to get a 10.9_ out of here I know its got it but I dont know if the driver can keep his stuff together. I want a 10 before I drop in the new engine the heads are done a flow like mad 306 cfm intake at .492 lift. Im hoping that the motor makes the power I want and if not the KB is up for sale and twin turbos are goin in. I might play with the bottle a little

Well if the Kenne Bell goes up for sale....I'll start the bidding at $500 for the complete setup :)

$501.01

$999.98 and i'll throw in Davids cereal

1/2 eaten box of rice crispies and a buffalo nickel. That's a good offer.

I would start with botle first Greg, seen great results with just a 75 shot with kb's and whipples, it will get you there for sure!

then I can call here a forced fed bottle baby lol

So how did the spark plug change go?

Forget the bottle,and get that 2sp powerglide.So easy a caveman can shift.

I really don't think there that much of a problem on mustangs, 5.4 3 valve trucks, your gonna probably break around 50% of them if it has 100k on it. Even with warming up and doing a induction flush on the trucks, they still break alot.

How did the plugs look Paul?

Feel any improvments?

Leonard 95 wrote:I really don't think there that much of a problem on mustangs, 5.4 3 valve trucks, your gonna probably break around 50% of them if it has 100k on it. Even with warming up and doing a induction flush on the trucks, they still break alot.

I have a 3v 5.4