This article is from the Chrysler-Plymouth-Dodge FAQ, by Dr. David Zatz with numerous contributions by others.
(Janos Schumacher) says: "A 2.5 is a stroked 2.2 so the skirt of the piston
goes past the bottom of the cylinder. This makes the piston wear away at
the cylinder walls making them slightly oval. The noise you are hearing is
known as piston slap and the only solution is to turn up the radio. Once
the car warms up the cylinders become more round and the noise goes away."
Chrysler's service bulletin says: Cold engine knock a few seconds after
startup, lasting 3-5 minutes most noticable at 2,000 - 2,500 rpm. Sounds
like valve lifter or tappet noise. Loudest in colder weather. Usually
disappears when the car is
Cold idle rough util coolant reaches 50-60 degrees F.
TSB 09-06-93 provides for computer replacement.