loss of power @ take-off

[SKEE bo]

I am the owner of a 89 420 SEL, the problem is this , when I drive the car all seems good from the first take-off but when I stop @ a light or slow to make a turn ,when I hit the gas the car loses power but does not shut off it kind of stumbles for a bit then power kicks back in
I just put new plugs in changed the oil the problem still remains
car has 168,000 miles and I have no maint. rec. all replys will be gr8ly welcomed
if anymore questions are needed just ask.