Seafoam will work fine to clean everything after the MAF sensor --
throttle body, intake, etc. You will have to find a way to have it
enter after the MAF sensor or you will ruin it-- through a port maybe.

Known as a wallet flush...
It's not part of the factory recommended maintenance.

You could attempt this yourself, but it will be right back like
it is now after a few hours running.

I'm sure the intake IS dirty- it gets that way because the PCV and EGR
systems dump "stuff" into it that tends to condense out in the
(relatively) cool intake manifold.  But I don't tend to do anything
about this unless you develop stalling or stumbling at idle. Then, the
proper procedure is to wipe down the throttle bodies and throttle blades
(you don't have a "carb" on a 2002 Caravan) with a rag soaked in solvent
such as carburetor or fuel injection cleaner. Dumping spoo like "sea
foam" down the air intake is a good way to do a lot more harm than good.

For what its worth, if you ever remove a very dirty intake plenum and
get down to the heads, you'll find that the fuel injectors and the area
they spray (including the intake valves) are perfectly clean because the
fuel spray keeps it washed down. The only area where the "dirt" can
cause a problem is around the throttle valves, which is why they get
WIPED clean with a rag, not blasted with a spray that will move dirt all
around the intake system. If you're not having problems, leave it alone.