Hello, I just recently got my new to me 2002 F150 V6 4.2L and the guy who sold me it said it definitely needs new spark plugs. My questions is what spark plugs are best for these 4.2L engines? I have heard of spark plugs breaking off in Ford engines but I haven't heard any cases in which it happened to a 4.2, is it a possibility? Which spark plugs will give me the best bang for my buck? An increase in MPG would be great, I average about 15.8 city. I will also purchase new spark plug wires, which brand would be best to go with? I have read that the 4.2's only take motorcraft plugs, is this true?

Thank you for reading.

 

Motor craft is prefered for both, I have had some luck with autolite plugs. The plugs on the 4.2 are old style in the side of the head. I would imagine if you tried real hard you could break them off , but that isn't an issue with this motor.

 

Thank you for the fast response mate! Which ones would you prefer?

 

Motor craft seem to be just a tad better, but I'm an old guy and drive that way.

Does your truck have any codes or has it just been a while since the plugs were done?

 

No codes at all, this truck is mechanically perfect (knock on wood)

I happen to drive very gently myself.

 

Motorcraft or Autolite are the preferred brands.

If you head over to www.v6f150.com, there is a sticky thread there that shows the part numbers for the recommended spark plugs, and appropriate gaps.

 

Go with motorcraft. That is the recommended plug and you'll have no issues with it.

 

I went with the Motorcraft's the guy at my local autozone has a F150 and he just happened to be there and told me that my engine is built especially for Motorcraft sparkplug's and I can'not go wrong with them. Thanks for all your inputs.

 

Stick with the Motorcraft. No matter how good the deal is or what you may hear, never, ever, ever put Bosch plugs in these motors. For whatever reason even gapped properly they make the truck run like crap.

 

don't wan't to hijack the thread but question?
When should be the first spark plug replacement? I also have a 4.2 (2007)
It currently has 45000 miles on it.

Thanks

 

they generally last about 60K miles. it wouldnt hurt to check on them but unless you start misfiring, i wouldnt bother

 

I got 84k out of my OEM plugs before it started missing - and the problem actually turned out to be the coil pack.