I have a '93 190E 2.6 that starts, idles, and runs fine when dead cold. Upon reaching operating temp, it idles a little rough and stumbles/hesitates when applying throttle from a stop. This car is from GA and never exhibited this problem until I brought it to DC where it actually gets cold in the winter. I would describe the symptoms as similar to those one would experience if one tried riding a motorcycle with the choke open. Does anybody out there have a clue what's going on here?

__________________
'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)