All,

New member here. Thank you in advance for any and all advise.

I have a 2006 Expedition, 5.4L with ~175k miles.

I purchased this vehicle from a friend, been having misfire issues since I received it. Thought they were all good until recently. I got a misfire on cylinder 3 code.

I went ahead and replaced all the coils and plugs since I didn't know when they were done last. (replaced with motorcraft plugs and coils)

On the freeway cruising and when it drops to a lower gear above 2000 rpms the engine basically falls on its face, until I let off.

Today it ran like crap, and ended up getting a ride to work. It threw out 3 new codes and the one old cylinder 3 code this morning and now I'm completely lost.

P0174- system too lean (Bank 2)
P0300- Random misfire
P0301- Cylinder 1 misfire
P0303- Cylinder 3 misfire

I just had a mechanic friend tell me to check the compression on cylinder 3 and go from there.

Has anyone else dealt with this?

Thank you

Will