Finally got my 2 Chrysler mini-vans to smog the other day. Both of the cars had vacuum hoses that were cracked and leaking causing the p0172 code to set(Fuel trim too rich). The hoses that were cracked were on the intake manifold side of the purge canister solenoid(on the passenger side of the car).
On the 1997 the 2 inch hose that connects the 2 hard hoses(just above the fan belt) that connect the purge solenoid(on the radiator hanger) to the engine intake. (I don't have a picture yet . . I'll get one soon.)
The other(on the 2002) was under and behind the throttle body. This one has a 90 degree angle to it that was cracked on the outside edge.
If all else fails follow the vacuum diagram under the hood and check all of the hoses.
