I am wanting to attempt a spark plug change in my 05 FX4 5.4L.

I am going to use Motorcraft plugs but have contradicting info as to the model number.

On the forum I have read to use SP479
Motorcraft.com says to use SP421
Ebay seller says these will fit AGSF-22-WM


Which ones should I go with?

 

421's = 3V

__________________

479's = 2V - and I believe are the successor or the AGSF-22's - (that's an old outdated number )

 

The 04-07 3V engines never used AGSF series plugs - they use PZT series. The AGSF's were for the 2V engines.

The truck came with PZT2F (SP421) and the recommended replacement is the PZT1F (SP462). They are less likely to stick and break.

 

Is this still the suggested plug for a 2005 with 5.4 V8 ??

Thanks in advance!

 

Nope.

It's now PZT14F ( SP507 )

MGD

 

MGD beat me to it , but yea, PZT14F since 04/2009.

 

Damn, no shiz!

OK. Glad I checked. The new model # is cheaper at rockauto to boot!

good plug? good deal?

Thanks again!

 

There is also a double platinum SP-515 now (at twice the price). E3 also released a 1 piece plug for it, and initial results are good. Long term results will take a while to show up. The results for the 1 piece Champions are quite mixed.

 

Champions suck the bawanna.

 

Go with the ones in my link??

$60.24 delivered @ RockAuto.