1991 fuel pump issues

I recently posted about my problem with my 1991 88 hesitation and miss. I pulled the tank to replace the fuel pump and filter sock and when I pulled the pump out of the tank, there was alot of black, rubbery crud of some kind inside the tank baffle and the filter sock was nearly black as well. I cleaned all the crud out and replaced the pump and sock. I buttoned everything back up, thinking that the problem was solved, but I still have a slight amount of hesitation when accelerating. If I accelerate slowly, you don't notice any hesitation, but it's still there when accelerating quickly. It's not nearly as bad as it was before. Anyone have any ideas? I did not change the fuel filter after the pump was replace as it was just changed last week in an attempt to solve the problem. Should I replace the filter again? Any help would be appreciated.

Yes that sediment can fill the filter quickly, other issues can cause the hesitation but start with the filter and post back.

Ok, I changed the fuel filter again, but that didn't seem to really help at all. I still have the hesitation. It doesn't seem to be a consistent hesitation, it comes and goes and is sometimes worse than other times. Seems to be worse when the air temperature is hotter. Anyone have any ideas? Any help is appreciated. Maybe the problem is in the ignition and not the fuel? The spark plugs were recently replaced (Delco), and the wires and coil pack were replaced a few years ago. I don't think the ignition module has ever been replaced and the o2 sensor has never been replaced. Could one of these be causing this problem? Also, the throttle body was cleaned a few years ago.
Please help!

At this point the guess work must stop, it should be scanned to check for proper 02 activity, maf inputs, tps functions and so on.

I just wanted to post an update to my fuel pump issue. I checked the tps, maf meter and the o2 sensor to the best of my ability with my voltmeter. I know that it would be best to have it professionally scanned, but my schedule doesn;t allow time to take the car to a shop. Anyway, the o2 sensor was not working properly, so I replaced it. This did not really help the problem, but it needed to be replaced anyway (original with 125000 miles). A friend mentioned that he had a car with similar problems and he fixed it by simply running a bottle of STP complete fuel system cleaner. I decided to give that a try and it has helped tremendously. I do not feel the hesitation at all during normal in-town driving. The hesitation is still there at times when accelerating quickly or pulling a hill but it is not nearly as bad as before. I guess my problem is just sediment in the injectors and fuel rail, as cinealta draiodoir mentioned in responding to my other posting. I am going to clean them out or have the system pressure cleaned as soon as possible. Thanks for your input