Got my truck a couple days ago and decided to change the plugs,wires ETC. It is a 99 f-150 4.2 140,000 miles 5 speed. when i pulled the plugs i was shocked they had a little white marker spot on the tip of the plug!!!! 140,000 miles with the factory plugs, i could'nt believe it,and they looked fine also. they was gapped like crazy but the truck ran fine. the only problem i have had is i changed all the vacum lines....

 

If you do replace the plugs..don't use Bosch. 99.9% of the time the motor will run rough with these plugs..even if gapped properly. Stick with Motorcraft, Autolite or Denso iridiums. For some reason these motors are very picky.

 

I'd recommend exact OEM Motorcrafts.

 

x2

Motorcraft SP-504s, gapped to .052"-.056"

 

I have 131,000 on original plugs and it still runs great.

Did you have any problems getting the plugs out, I am wanting to change mine myself but am a bit nervous from all of the stories I have read.

GOD Bless,
jerry

 

The only one that I found was a PITA was the one closest to the firewall on the pass. side. Unless you have a few swivel heads for your sockets prolly best approach is to take off the front pass wheel and access it from the wheel-well.

 

The horror stories you are reading are for the 5.4 3 valve V8. Our V-6 plugs are a piece of cake as long as you can reach them.

 

So as far as it being an aluminum block there is no precautions I would need to take to make sure that nothing breaks or strips

 

No precautions that you wouldn't have to take with any other aluminum head.

 

thx, one more question, I have never had an aluminum block before, is there actually something I need to know that is different from the a steel block

 

dont over tighten em!

 

so breaking them loose is not a problem

 

anyone

 

i havent ever had trouble breaking them loose...busted a few knuckles but never damaged the head..

 

k, thx for all the help, will try it tomorrow