2003 Caravan A/C drain leak

2003 grand caravan sport(bought as new 01/2004)
3.3l engine
52k miles
with rear a/c
mobil 1 oil and regular air filter changes
HAS BEEN VERY DEPENDABLE
Nuances are: (major issue is below)
-sluggish exceleration, past 10,000 miles
-ticking type of sound coming from idler pulley area when cold, goes away when warmed up.
-fairly minute shudder when trans shifts in low gear. I have felt it from day one but no one else could (dealer mech. Included)

REASON FOR POST!
Water seems to be leaking from the interior side of where the drain goes through the firewall(soaked carpet. On the exterior side the drain looks incomplete. It is a hard plastic tube sticking out of the firewall about an inch long with a slot cut into the under side of it. It looks like it should have a rubber elbow on it or something. The water that does come out the ext. Side seems to run back to the firewall insulation and then down. I need to know how bad the problem is or is it just a clog situation. I did try some compressed air and the air went through but did not stop the interior leak.
Thanks for any help.

Rick