91 240 shifting issue/fuelpump issue

[Vancethevolvo]

I have a 1991 Volvo 240 wagon auto-transmission, I started having an issue with the car losing power shortly after I heard the fuel pump buzzing. Well I changed the in-line pump with a Bosch pump and I still heard the buzzing so I changed the in-tank pump and sending unit together with a VDO unit.....I still hear the buzzing very loud and most of the time the car takes a long time to shift but very occasionally it shifts fine. Could it be that the in tank one just isn't getting power?