I know this has been beat to death, but I figure we can beat some more, I have an 06, scab 4x4, 25000 mi. I had it in the Ford dealership for some warrenty work and got to talking with a tech. about the plug issues, this dealership only changed a couple sets of plugs so far (@ 100,000 mi) and had an issue with one truck, had to pull the heads, they have the proper tools and equip. I read in this forum that alot of people chng. @ 50,000, when I asked about changing plugs this soon I was told it would be elective maint. so if they broke plugs the cost would be on the customer, but if you wait until Ford recommends changing @ 100,000 we are almost assured breakage. What should we do? It looks like we all have to wait until our trucks get to 100 k mark and hope for the best

 

Or sell it before you reach 100k, If it makes it....

 

I would think while under warranty you might have more leverage with FOMOCO. Also as mentioned if you do it sooner the failure rate seems quite a bit lower. I would say call a couple dealerships and feel them out. See what they do in the instance once breaks and go with the dealership that gives the best answer. I would shoot for right before your 3/36 is up. Make sure they add anti-sieze to the new ones or it would be all for nothing

 

I've broken them in engines with as little as 15K miles. On my truck, I replace them every 30K.