Which Plugs for my 03 GT

Burtonsnow157

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Dec 16, 2007
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My car is at 41000 miles. Its not driven really really hard but i do get on it from time to time. My mods are in my sig (light mods) and im doing an oil change in a few days so i figured i might as well get a new pcv valve and spark plugs

first off, Should i skip the pcv. . . . skip the pcv and the plugs?

If its a good idea to replace the plugs, which ones should i get. I've done research and pretty much decided the motorcraft brand is best to go with but which ones should i pick up. . . dead stock ones or maybe a heat range lower with slightly tighter gap for a little better performance or something?
 
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From Randy, "if you want stock platinum heat range in a Motorcraft, it's a AGSF-32-PM which is now a SP-493, if you want the same heat range in a copper core, get a AGSF-32-C or SP-447"

You probably don't NEED to replace the plugs now, but it couldn't hurt (assuming you install them correctly). The coppers are a little better for performance, but you have to replace them about every 30k miles. You should replace the PCV valve every 30k miles.
 
"if you want stock platinum heat range in a Motorcraft, it's a AGSF-32-PM which is now a SP-493, if you want the same heat range in a copper core,

although the coppers have less longevity is it safe to assume that those are better than the platinums in our engines?
 
I would leave them alone!! Too many cases where they blew out on people and took the threads in the head with it. This guy at works daughter has 92K on her 99 GT and it still runs strong.

If you do change them, blow out the holes before you pull the plugs, and torque the plugs to 13ftlbs.
 
If you do change them, blow out the holes before you pull the plugs, and torque the plugs to 13ftlbs.

yeah im gunna pick up a can of compressed air and try to wipe out the holes before i pull the plugs out.

also, i have a 1/2 inch drive clicker type torque wrench (its pretty big, and the lowest torque is 10 ft/lb). . . do you think i should pick up a 3/8 drive tq wrench to fit better and probably be a little more accurate since the range starts lower?
 
yeah im gunna pick up a can of compressed air and try to wipe out the holes before i pull the plugs out.

also, i have a 1/2 inch drive clicker type torque wrench (its pretty big, and the lowest torque is 10 ft/lb). . . do you think i should pick up a 3/8 drive tq wrench to fit better and probably be a little more accurate since the range starts lower?

Do NOT use 1/2" drive. Get a good Craftsman 3/8" drive wrench. Don't mess with Harbor Freight tools either, they are not accurate and you don't want to be off when it comes with 4.6L spark plugs.

Now....the truck 4.6L and 5.4L are the worst. My buddy called me today and just told me he changed plugs on his 5.4L F150 with 110K, on Saturday. He said he had no problems. I told him to call me if something happens because everytime I have talked to someone about tuning up a truck motor, they say don't do it, they always pop out.

Overall, just be carefull. Do not over torque them, that is the main reason for failure. I had to pull a couple 4.6L plugs from my 01 GT and when I put them back in with my fingers turning the extension...I let them get snug by hand, then put an 1/8 of a turn on them. I switched to the torque wrench and that was right at 13 ft lbs.
 
Overall, just be carefull. Do not over torque them, that is the main reason for failure. I had to pull a couple 4.6L plugs from my 01 GT and when I put them back in with my fingers turning the extension...I let them get snug by hand, then put an 1/8 of a turn on them. I switched to the torque wrench and that was right at 13 ft lbs.

The torque spec is 11ft/lb's for the plugs right, and 89 inch/lb for the c.o.p's?

i'm honestly not too worried about the job cause the way i look at it is, if i do everything right and torque them correctly, the ones in there do eventually have to come out . . . . if blow out in these motors is as common as they say, then you still have to face that problem now or later. . .

a blow out or any other problem is bad, and i'd obviously rather have that happen at like 100k than 40k but its technically all the same in the long run
 
although the coppers have less longevity is it safe to assume that those are better than the platinums in our engines?



Yes. Copper is a better conductor of electricity only surpassed by silver. (yes there are silver spark plugs)


However, out ignition is COP and designed for copper plugs, so IMHO the difference in performance is negligilbe.

However, don't buy the Bosch "gimmick" plugs. Stock with OEM motorcraft plats.


You could go a little bit longer before doing plugs. I currently have 65K miles on my originals and i can lug 5th gear and not get a misfire at all still.

Been meaning to do them...just lazy. That's prob why i'm putting plats back in