My 03 F150 XLT is at 50K. Ford says to wait til 60K to change rear end grease and plugs. A buddy of mine says the aftermarket plugs and wires are good on his 03 4.6L. I am debating whether or not to replace with OEM or if aftermarket are just as good. Any comments would be appreciated.
My modified 4.2 now gets 23 mpg on the highway and 20 City. I take good care of it and want to make sure the plugs and wires continue to compliment the power, mileage and life of my truck. I have added an oversize tranny cooler, air in-take, throttle body spacer, Jegs super chip, along with all the electronic toys inside.
Dont want to just throw any plug and wire set in here!

Thank you.

 

You can check with us in the 4.2 forum for more info (several threads in the past regarding plugs) but my opinion:

Go with Motorcraft wires.

As far as plugs: Motorcraft Platinum or Champion or Autolite Cpper plugs, if you don't mind changing them at 20,000 miles give or take a few K.

Folks have tried all different wires / plugs and seems as often as not, something other than the above just doesn't work out OK.

I have put over 225,000 miles on two diff 4.2 F150s and the above mentioned have worked perfectly each time I have used them.

FWIW, there's a thread in the 4.2 forum where one of the FTE Sponsors saved a 4.2 guy quite a few bucks on OEM plugs and wires, when compared to buying from his local dealer.

Now that Rocks!

 

Why change what works? Go back with factory Motorcraft parts!
Myself,I use Motorcraft plugs but different wires.I like Motorcraft wires but prefer anything with a lifetime warranty.

 

Thank you for the advice. I want to be sure I continue getting the power and mileage for as long as possible.