SP546 Spark Plugs direct replacement?

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WolfgangFox

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Hey All,

Been reading about these SP546 spark plugs that are the one piece design. Can I install those into my 2005 Expy 5.4l 3v with no boot changes or anything?

I keep reading about black and brown boots, do you have to have the brown boots to even change over the plugs, or does it matter?
 

BigOleFordFan

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Is that the plug that is spec'd for your 05, and how long has it been since the last boot/plug change ?

If it is the correct plug, you have to remove the boots to get to them anyways, so if it were me, I would change them all at the same time.... generally speaking, new plugs + old boots (or vice versa) is a bad idea....

As for brown or black boots, then I suggest you research that some more, because from what I have been told by my trusted mechanic of over 10 years, they are NOT interchangable :)
 
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WolfgangFox

WolfgangFox

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The plug that is spec'd is the piece of crap 2 piece that causes oh so many problems with the 5.4l 3v engine. Several posts have been made about it here.
I don't know how long it's been. I just bought the expedition from the 2nd owner about 3 months ago. He had it for 3 months and bought it from the NM DOT. The reason I am asking was I had a misfire which was a bad plug. My mechanic got the plug out easily (phew) and he actually installed one of the SP546s in it's place. LOL So the answer to my question, for the last 2 days, is yes it works. We'll see how it does long term, however several others have replaced their's and they seem to work well.

I'm concerned about just taking out the spark plugs if they are all the 2 piece design, because of damage. So I don't think I'll be changing them until I can get the maintenance records from the NMDOT.
 
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