Chrysler Repair: 2003 Voyager: codes 0121, 0442/0455/0456, manifold vacuum, vacuum level

Question
Hi, I have a 2003 Voyager with 105000 miles on it.  It just started jerking and grabbing whenever I de-accelerate.  It is worse when warmed up.  Occasionally stalls when I stop, especially after highway speeds.  I did the codes and got the following: 1684, 0121, 0442, 0455, 0456.

Answer
The 0121 code says there is a disparity between the MAP sensor reading of the intake manifold vacuum level and the actual opening of the throttle and the rpm which suggest a different manifold reading. Either sensor could be inaccurate or the wiring to either of them could be impared. So look over those wires for signs of melting of the insulation or other damage. There is an 18-step procedure shown in the maual to sort it out.
The 0442, 0455, 0456 all have to do with fuel vapor recovery system having a leak ranging from small to large (which may reflect the history of the problem). There are many hoses in the system that connect the fuel tank to the carbon cannister and the leak detection pump so it would be good to trace those to find a cracked hose or disconnected end/fitting. A loose or fault gas cap can also cause the problem so start there.
Another idea, because the intake manifold is involved with both systems, is that the vacuum hose to the intake manifold that brings the vapor from the canister to the manifold may be leaking or is disconnected.
Roland