2001 chrysler t&c 3.8 has a misfire in #2 cylinder . how to pinpoint cause ?

This is a very common problem....and can be a little difficult to troubleshoot.
How long since a tune up?
My 01 did this same thing at 80k miles..ended up being a bad coil. VERY easy to replace, so don't take it to a dealer unless you don't want to do minor wrench turning.
I first did an entire tune up with new plugs and wires....didn't help at all. I measured the resistance of the ignition coil assembly and found that #3 was reading lower than the rest even though it was "in spec". After replacing it, the van has run for thousands of trouble free miles! Worth every penny...gas mileage went from about 14 back to 19! Paid for itself very quickly.
The shocker in all of this was that after doing MUCH shopping around for a coil, the Dealer was the best price at around $80-90. Even Autozone and others were over that price....go figure.
IF you have not tuned it up in a while, pay the extra for a new set of plug wires and new OEM plugs and have them installed by someone competent. Getting the spark plugs installed at the rear of the 3.8 is not a whole lot of fun. I did it myself, but only because I enjoy working on my vehicles.
GOOD LUCK!

If it has factory wires it might be time for a tune up how many miles does it have can you feel the misfire i need more info