major hesitation when accelerating

I have a 97 Continental that is in great shape, except it has a lot of hesitation when accelerating. It seems to get a little better the longer you drive it. I tried putting some injector cleaner in the tank, but that doesn't seem to be working.
Any suggestions?

check your filters to make sure there clean, although it sounds alot like you need new fuel injectors/spark plugs. you should do a tuneup which includes all the above and more every 30thousand miles.