Hey guys I'm new to the forum and I recently bought a new to me 2012 with the 3.5L ecoboost. I decided to change my plugs out because it was getting lower than normal MPG's. Everything went fine until I went to plug in one of the coils and the connectior won't plug all the way onto the coil. Any thoughts on what it could be and possible fixes.

 

Did the secondary lock get accidentally pushed in while you were messing with it? This would jam up the connection and stop it from fully seating. Other possibilities are bent terminals or the connector was damaged when you took it off. This happens sometimes because people don't understand how to take the connection apart and use a screwdriver or pick and break stuff.

 

It's not the secondary lock or a bent pin on the coil
I checked those already. The connector was stuck on so I hit it with some electrical connection cleaner and worked it off by hand I've had experience breaking the pigtail before 3 of the coil connectors on my old 5.4 3v broke on me and were held on by dielectric grease. I'm thinking a terminal in the connector is messed up because I can push it part way on and it will run fine it just won't seat all the way so it can wiggle loose. How hard is it to splice a new pigtail on I'm a fairly competent wrench turner I just don't have a lot of electrical experience.

 

I think they make replacement connectors that aren't too expensive. I would try this route. You will also need to tool to depin the broken connector.

FYI, the easiest way to take these off is to unlock the secondary lock, push in on the connection while holding the coil, THEN push down on the latch. It should pop open. The rubber ring that seals the plug puts a load on the latch and binds it up. Pushing in takes it out of the bind.

 

Thank you Wookie with my old 04 I learned a lot through trial and error but with this 2012 being the first truck I have financed I would like less trial and error and more get it right the first time.

 

The rubber O-ring on the connector can get out of alignment, and dry. Try a small amount of soapy water (or non ammonia glass cleaner) on the weather seal O-ring and see if it will seat correctly