90 Civic Si stalling problem
 

My 1990 Civic Si stalls as I am coming to a stop less than 25 mph when
the gas tank is at half or less than half. When it is over half it
runs perfect. So far I have replaced the fuel pump and fuel filter.
One thing I noticed which was weird my friend got diagrams from our
local honda dealer for replacing the fuel pump. It is supposed to be
located under the rear seat under a silver panel. I disassembled this
and all I found was the fuel gauge. After dropping the tank I located
the fuel pump on the back left side of the gas tank.
My suspiscion is that an aftermarket fuel pump was put in the wrong
area of the tank thus when the tank is less than half full then pump is
not pulling fuel. This makes sense to me because when coming to a stop
the gas would shift to the front of the tank(where the fuel pump should
be located) and since it is located at the back of the tank the fuel
pump is just sucking fumes and very little gasoline.

Does this make sense, any suggestions? My next step was to relocate
the fuel pump at the OEM location(under the rear seat) and perhaps it
would reach the bottom of the tank better and would fix my problem?