Is the spark plug change difficult on the ecoboost 3.5? Would you change the plugs from the bottom or the top>?

 

Ridiculously simple. You do it from the top. Remove the oil fill cap and the cover pops up from the front on both sides of the engine and then pull it towards the front as it clips back towards the fire wall.

 

Easiest plugs you'll ever change. The most time consuming part is unfastening the coil wires.

 

I did them this winter on a friends truck for him.
Super simple to change.

 

Sweet! Tried to my Hemi and it was a pita.

 

I changed the plugs successfully, and you were correct, it was easy! But it did help to watch a couple of You Tubes for tips on how to take loose the electrical connections. I am a backyard mechanic not used to technical details of today's engines. Thank you for the replies, I appreciate it!! 4 of the plugs were wider than .55 inch (supposed to be .30 inch). My engine seems to have even more power than it had, and I hope the mpg will increase! One thing that was recommended that I didn't have was the rubber boots that go over the spark plug. I will have a new set of those the next time I do this.

 

I found out in adjusting the gaps on the plugs; I scraped off some of the iridium or platinum or whatever those plugs are coated with. I started to get a tick in the rpm of about 50 rpm when idling (every 3 or 4 seconds) . I brought it in, and 2 of the plugs I had put in were off just a little bit on the scope. I had lost or misplaced my good spark plug gaper tool, and live out in the sticks, so I banged the plugs until I had the right adjustment and must have scraped off part of the coating. So, I will replace the other plugs that might fail in the future because of using inferior tools.

 

changed plugs and engine runs very rough under lots

 

I changed spark plugs with correct gap (.03) and engine runs very rough under load.

 

You should do two things... Get new spark plug boots, and drill the intercooler weep hole. That will get you fixed up.