'94 E320 Transmission, won't upshift cold, o.k. hot

[Ron Johnstone]

My '94 E320 Wagon with 94K miles has, for the last 5 years, not fully upshifted into 4th until about 2 miles of driving. Today, it wouldn't upshift from 2nd gear until the car was fully hot. Once hot, it shifts just fine. Level is o.k. and fluid looks clean. Suggestions would be much appreciated.

Probably unrelated, but it has also developed an occasional miss at idle. Not enough to stall but very noticeable at about 700 rpm. I replaced fuel filter and changed plugs but no help.