回複：it is not hard to change them, it is hard to access to them.

Agree. Will find out.

Anyway, a Chinese mechanic quoted about $300 for replacing spark plugs. It's about 2.5 hour job which means it may be hard to access them.

It's still cheaper than the dealer's $700.

They both said it's not necessary to replace coils if engine light not on because of coils. I don't know. It's known Aviator has coil problems and Ford even has extended warranty for it (volunteer).

Seems the oem coils are not cheap as I thought, about $50 a piece from www.autohausaz.com. May be leave them this time.


The Chinese mechanic recommends engine tune-up which also replaces PCV, etc. Any advice on that? Is it good to do a whole tuneup?

Thanks a lot.