Single Cylinder Compression Loss.

[Andrew White]

2018 Ford Expedition Max 3.5 Ecoboost
Phasers replaced and upgraded/ new transmission 25000 miles ago.
I started getting a camshaft phaser code on the way back from a trip. I took to the dealership thinking it was the phasers again. No rattle on start-up. The dealership called back and said that it was a spark plug/coil. When I told them that I tunned up with new boots and plugs 6000 miles ago. They ran a compression test to show loss of compression on one cylinder. ANY INFO OR HELP APPRECIATED.....

 

[Fizzy]

What help or advice are you hoping for? Sounds like you need a teardown to figure out what's happening in that one cylinder. The

2018 Ford Expedition Max 3.5 Ecoboost
Phasers replaced and upgraded/ new transmission 25000 miles ago.
I started getting a camshaft phaser code on the way back from a trip. I took to the dealership thinking it was the phasers again. No rattle on start-up. The dealership called back and said that it was a spark plug/coil. When I told them that I tunned up with new boots and plugs 6000 miles ago. They ran a compression test to show loss of compression on one cylinder. ANY INFO OR HELP APPRECIATED.....

You're out of brand/model specific territory here, and into general mechanics. Sounds like you need a tear down. By "tunned up", do you mean tuned? You got an ECU tune?

 

[Andrew White]

No "tune up" such as plugs and coil boots. All stock.

 

[JamaicaJoe]

Leakdown test with and without oil added to cylinder to rule out ring leakage vs valve stuck?

 

[Benztech]

Do you have the compression test result? Loss of compression is a generic statement since there are specifications for compression. They should be able to provide the spec and results for all cylinders tested. Next step would be a leak down test as Jamaica said.

 

[apex96]

May not be related but it looks like there are some gen2 3.5s that are experienceing roller follower failures... https://www.youtube.com/shorts/YL5Q0MUW3FU