2014 F-150 screw with 3.5L V6 EB, 125K miles

Had a plug/coil fail recently. Replaced. All's well. Considering replacing the other 5 coils/plugs.

Should I do this if I'm not having any issues other than probably some fuel effciency loss?

 

plugs absolutely

coils no

 

why not the coils? Do new coils offer any fuel efficiency?

 

no they don't, when they fail, replace them but the 3.5 eco boost was / is not known for coil problems

 

id echo doing all the plugs - just inspect the coil boots closely and be prepared to replace them. If they're original they might tear or show signs of aging when taking them off the plug.

 

factory coils rarely ever fail. But the boots/springs are maintenance items. If you had factory coils and if you didn’t toss coil, I’d try it again with a new boot/spring.

id never change plugs without also changing boots/springs too. YMMV.

 

agree with the post above. Coil boots today are the equivalent to plug wires back in the day. They should be replaced when doing a "tune up" and if coil is having issues, replace all the boots as a preventive.