Hello all,

The title basically says it all. When under hard (2000-3000 RPM) the passenger side of the of the engine sounds like it's a machine gun until I back off a little. Just had the oil change done, and all spark plugs replaced. It's a 1999 Expedition EB edition with 230,000k (roughly 115,000 miles) on the engine. Problems just came up begining of this year, thought it would work itself out, but didn't. Mechanic is at a loss to explain it.

 

Sounds like the passenger side cam phaser is worn out

Check out this thread...
https://www.ford-trucks.com/forums/7...placement.html

 

I would check the spark plug torque, seeing how these motors like to spit them out. Have you checked the exhaust manifolds they can develop leaks over time?