Chrysler Repair: Sensation of misfire, dodge caravan sxt, 2005 dodge caravan

Question
QUESTION: Hi, Kevin,

I have a 2005 Dodge Caravan SXT (SWB built in January 2004) with the 72,000 miles on the 3.3L V-6.  The problem I'm having is with a sensation of a misfire (kind of an on/off power feeling) while driving between 25mph and 50mph.  There are no codes in the computer, and the problem has continued even with new platinum plugs, spark plug wires and the Chrysler fuel system cleaning (done by the dealer).

To me, it is quite noticeable... would you have any idea what might be causing this problem?

I would really appreciate your help,
Charlie

ANSWER: did the dealer drive it with the DRB on the van while driving  the scanner can see a misfires that humans cant feel.

---------- FOLLOW-UP ----------

QUESTION: Would a misfire be stored as a error code that could be retrieved later?  

Someone mentioned the transmission as a possible problem, something with the lock-up function?  Does that make sense to you?

Could a problem with the catalytic converter, or perhaps a front wheel bearing, cause the sensation of on/off power?

Thanks for the help!

Answer
if it is common enough that the computer sees it enough yes it will set a code.
A converter has nothing to do with it

as for what U feel  I cant tell over the internet  I can only use physical hard evidence like codes and sensor readings  anything more then that u would haft to have some one drive it and see whats going on from there.