I have just over 77K on my 2006 GT and I'm thinking about doing a tuneup before the winter hits (yeah I know long time off LOL), but hearing/reading stories of Spark Plug Problems with the 3v 4.6L V8 gives me pause of doing it myself. I've done tuneups before and worked on my car with out screwing up anything too badly and spent 4 years in the Army working on Diesel engines on Bradleys (which I hated)...

so should I be able to do this myself, or should I just take it to the dealership and have them do it?

 

I've replaced mine 4 times and I've never had a problem , but the longest time I went between changes was about 18K miles. The longer the time the more they will be corroded and the better chance of breaking one. With the length of time on yours I would follow the TSB pretty closely if you do it yourself. Also be aware that if you have the dealer change them and they break a plug they will charge you to get it out, I know this doesn't sound fair but several members on here have had this happen. I would also go to a one piece design when you replace them so you don't have future problems ...

 

I have changed mine twice at 60 / 110,000 with no problems, but was scared too the first time with all the problems I read. Slow and easy!!

 

It took me 24 hours to change my plugs the first time.

I let the car cool.
Loosened each plug
Sprayed PB Blaster and allowed it soak (don't over do it)
Wait an hour
Loosen some more
Spray
Wait
Loosen or work back and forth (whichever feels better)
Repeat

My plugs were screeching to all hell but they all came out.

Also in my opinion if you go to one piece plugs, don't get Brisk unless you need a non-stock heat range plug. These plugs are total garbage.

Get the Champion plugs.