Ron,
If you could post a few more details, it'd help track this down. Things like current mileage, how it's been serviced over the years, last time plugs were changed, and whether distributor caps and rotors have ever been replaced.

Does this get better when the engine warms up? Does it run OK at highway speeds?

Any other changes in its behavior, like drop in gas mileage?

Just a longshot, but mine will have a very rough idle the next time I start it if i happen to run it just a little the time before. For example, I start it up just to back it out of the garage to wash it, then later start it again to put it back into the garage (without letting it warm up). I can guarantee that the next time I start it, it'll stumble, and sometimes flood.

__________________
Steve
'93 400E