I am at 120,XXX with my Ex. V10.
As I took out the front two plugs I see they look like originals. Before continuing I ordered coils and will wait to finish the job. You who have replaced plugs know that at my mileage it would be a shame to put in that work and not replace coils at the same time. I figure at my mileage they are due. should I order also a pvc valve and fuel filter? where are they located?

 

details matter

what brand coils did you order ?

 

If you don't know the history of the plugs and coils yes you are right to change them. The rear two on the passenger side are the most difficult. I just did them on mine. The pcv is on the passenger side valve covers. Fuel filter right under the drivers seat

 

I ordered Motorcraft Coils and I believe the coils that are now in it are original with the plugs as well.

Were is the pcv valve located...only 1 is this correct? Also thank you for letting me know where the fuel filter is.

Will I see a noticeable increase in fuel mileage with the tune up?

 

I'm firmly in the camp that says COPs are good until they fail, mine are all still factory at 130K and working perfectly fine. Be sure to keep your originals around as spares if ever needed, they are still good to go.
I hope you found a good deal on 10 MC COPs vs the typically cheaper Denso units that are actually the exact same coils as Denso is the OEM manufacturer for them and under the Denso sticker they have the MC part number printed on them.
What plugs are you using (and what came out?) and what torque value will you be using? What year is your V-10? (Short threads or full threads?)
Access to the COPs (and boots) really isn't an issue, it's dealing with the plug wrench extensions and ratchet that are the pain in the rear.
Just 1 PCV valve and as was said above it's in the pass side valve cover, be careful with the hose off of it and check it for cracks.
For the fuel filter it's best to pull the pump fuse and let the engine stall from starvation, that takes the pressure off the filter. Again be careful with the plastic bits on the filter release fittings, there is a very recent thread that covers this.
You should see a little better throttle response, quicker starting and slightly better fuel economy following the plug change. My best ever towing trip mileage came immediately after a plug and boot change.

 

Speaking from my own experience, mine ran much smoother all through the powerband when I put in new sparkplugs and COPs. Granted, mine has 267k, so it's a little further along than most, and the previous owner did nothing to take care of it.

Use this tech folder to your benefit. It has information on nearly everything you need for your Ex.

 

I'm with @WE3ZS on the COP replacement. I carry an extra Denso in my 99 F250 with 168k miles. I have changed two or three coil packs and the rest are original.

Torque your Motorcraft or Autolite plugs to 20-25 ft-lbs. Factory 9-14 is far to light.

This gearwrench spark plug kit helps a lot too.

GearWrench Tools KDT41740 Magnetic Universal Spark Plug Service Kit, 5/8-Inch, 3 Piece https://smile.amazon.com/dp/B000NIEECO/ref=cm_sw_r_cp_apa_i_IwdtEbAKG6KQA

 

X3 on replacing coils only when needed.
Our Excur has 140K and OEM coils, except for one that had a broken hold down tab after the spark plug blew out.
Our Exped has 170K and OEM coils, except for one that had a broken connector after the first time I changed plugs.
I've change plugs (Motorcraft) and boots (Denso), once on the Excur and twice on the Exped.