Need to put a set of plugs in my 99 f150 (4.6L) and was wondering how these motors run with the platinum plugs versus the standard autolite 764's, it it worth the extra money for either the double (AP764) or triple (APP764) platinums??
From what I see it looks like these motors came stock with platinums.

 

From my personal experience, spark plugs are not going to make a night and day difference. Some say they they see a difference, but I dont. That is as long as the ones that you are replacing are still functional and not worn out. I am sure this will start a nice discussion.

 

Platinums are standard and I wouldn't try anything other than spec.. Motorcraft only.. Do a search on spark plugs in this forum - hate to see any body go through what I did when I tried to run something other than motorcrafts, I wasted money and to do a plug change twice.. Not fun!!

 

Run the platinum as stated. The only plugs listed for the 99 5.4 are double platinum. And stay with motorcraft for better results.
hllon4 is correct for most engines, but these mod engines Ford builds are a little more picky. Go with the safe bet and run what ya had for OEM.

Sled...

 

i would stay with the motorcraft unless you want to spend some money, the denso iriduims(know thats not spelled right) are a way better plug in my opinion but are pretty pricey, good luck

 

Go with the stock Motorcraft plugs (mine lasted 102K and could have gone longer) or the Denso Iridum plugs (what I have now).