Sharing my experience...
I stuck w/Motorcraft. I bought my 17 having about 42K miles and I just changed the plugs at about 85K, doubtful the plugs were changed prior to my ownership. Overall, pretty easy job. I'm slow and it took me a little over an hour once I knew what I was doing.
Couple things I did & learned:
1.) Be careful w/the coil plugs, do not break them. You must pull the red slide back and press the latch down, and it should slide out easy. Take your time, they will come out.
2.) I used a 10" extention magnetic 5/8" socked and it worked great except the furthest back passenger plug (not sure what number it its). I used a 6" version of the same tool for this particular one. I twisted slow and they came out pretty easy.
3.) For the cost, I replaced the coil boots. Super easy to change and a no-brainer for the money.
4.) I torqued my plugs to 9ft/lbs and used silver anti-sieze on the treads. Once the plug is put down the tube and making contact, I rotate the plug backwards a couple times to coat the threads on the block, and switch direction and feel by hand for the catch.
6.) Be careful w/the dielectric grease. Only coat the inside walls of the boot and the ceramic bumps of the plug. I used a Q-tip. Do not goop the ends of boots (squeeze blob) as it may introduce a resistive path between the plug and boot contact and cause severe electrical problems. I noticed this was the case when removing the old plugs as the terminal was covered w/grease. Although I didn't have any existing problems, the grease is not intended for application on metal and not designed to pass excessive electrical current. I applied a very thin film of grease on the rubber coil seal to maintain flexiblity and extend life of the seal. I also added a very very thin coat on the coil connector to make removal easier next time. Just my preference.
7.) Torquing down the coil - I tried the recommended 63ft/lbs and broke the aluminum bolt. Not sure what happened. The bolt may have been previously weakened? Interestingly enough, I was able to remove the broken bolt by hand. I was fearful in having to do doing surgery with my vice-grips and PB blaster. There must be some sort of internal fastener clamping the two surfaces vice the traditional threaded hole. I bought a new bolt for ~2.00 at the local dealer and used a calibrated hand to secure the coil packs.
8.) Plug Gaps - When measuring the gaps of the old plugs, they read about 40-42 thousands, almost 10 more than the recommended gap. I can only assume over the course of ~80K miles, they expanded over time which probably negatively impacted performance. I didn't have any issues prior to and I was still getting ~20 MPGs on the highway. The new plugs were gapped at ~ 32 thousands by the factory and used as-is.
Overall, the plugs were due for replacement (see pics below). I should have replaced them sooner. I purchased all of my parts on Rock Auto and I enjoy working on my own vehicles, not to mention it's an opportunity in teaching my kids basic mechanics. If you've maintained cars before, this job is pretty easy and you'll save about ~$200 (labor & taxes) and know the job is done right!
Hopefully folks find this usefull!
(Passenger (left) <--> Driver side (right))
(Front (bottom) - Back (top))
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Grease on the terminals
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Passenger side
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Driver side
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