Necessary, no. Recommended, yes.
120k miles.
No. Timing belt replacement is possible in vehicle.
very!
Yes.Yes.
Your 2001 Dodge Ram does not have a timing belt, it has a timing chain. No replacement is necessary.
The 2007 Ford Focus has a chain and not a belt. No replacement is necessary.
It is not necessary to change timing gears when changing a timing chain unless they have become worn. You won't know if this is the case until you get the cover off and inspect them. It is necessary to change any chain tensioners when you change your timing chain.
There is a "reset" function in the Chrysler scan tool.
The 1990 Buick Century has a timing chain and not a belt. No replacement is necessary.
You don't Replace the timing belt at the recommended interval. If the engine is apart for other service any measurable wear requires replacement
The 2.4l in a PT Cruiser has a timing belt.
The 2004 Toyota Corolla has a Timing Chain and not a belt. No replacement is necessary.