When I search in this forum I get two different answers for the correct plug # for 06 F150 with the 5.4L. I see the search said the newly redisigned plug was the sp507 and the sp515. Which one is it? Thanks in advance getting ready to do it this weekend. Any advise on which to use would be appreciated!

 

SP515 is the correct one.

 

The sp151 is the new plug according to my mechanic they break to he's had other customers that have put the new one in and for one reason or another hadto change and they break.

 

I doubt that very much. The electrode end is narrower on the updated SP515 plug meaning its not near as likely to stick in the head which is what is causing the breakages.

 

I knew they supposedly redesigned recently! thanks for info going to tackle it today and tomorrow!