1994 Chevy Beretta Surging

I am trying to figure out what could be the cause of my surge issues under constant load. Originally the issue of where it felt as if someone was slowly pinching off the fuel line only after about 2-3 minutes in drive and while driving then would stop at about the 5 min mark. Now, it happeneds after that 2-3 minutes and does not go away.
If I hold at a steady speed, the vehical will near choke itself out and get a load of fuel at the last moment and jump forward or I am able to go to full/near full throttle to get fuel into the engine.
The fuel filter was replaced and it has helped very little, but none-the-less, replaceing it has made a noticable change in how the vehical runs.
I receive no codes and I have not been able to find anyone that can test for the issue since it only seems to occur while driving. So I have been told everything from fuel pump to injectors to head gasket to transmission to exhaust. The one local mechanic I have trusted throughout the years said right to me "I don't know" which so far is the best answer iI have recieved.