I have a 4.0 V6 engine. I am looking to change the spark plugs.

I notice that some people are running double platinum plugs and everything else for their trucks. Now on autolite's site there is just one plug that is single platinum even. It's the AP5143

My question is, I accidently got a set of APP104 autolite double platinum because they with in the 3.0V6 engine. the thread, and reach are the same.

Now the APP104's have a heat range of F14? with a gap of .044
The Ap5143's have a heat range of E14 with a gap of .054

What is the difference in these heat ranges? and... if there is not a differance, couldn't I just regap to the .054?

 

it shouldnt make a difference in your truck at all

 

5144 is the correct Autolite plug number for the 4.0L SOHC.... I don't see 5144 anywhere there...

Can't help you on the heat range inquiry. But you already paid for Double Plats, go exchange them for APP5144's.

 

just get Motor Craft plugs.

 

Stock engine stock plugs. Changing heat range won't help any.

 

HI!... I run AUTOLITE AR-103's. They are one step colder than stock due to my nitrous.