Had a similar problem with my 93 400E. When I backed out of the garage in the morning, there was a couple second lag before it kicked into drive. Dealer put 2 transmissions in it and the problem never did get resolved. Has 72K on it now and no other issues have arisen with the tranny. Just how it is I guess.
95 SL500 Smoke Silver, Parchment 64K
07 E350 4matic Station Wagon White 34K
02 E320 4Matic Silver/grey 80K
05 F150 Silver 44K