1978 262c Bertone

[E80Bertone]

Hi. I just became a member of this forum. I bought a 1978 262c Bertone a year ago. The mechanics who worked on the car refurbished the whole engine and the transmission. The problem now is that the car jerks after 4 to 5 min starting the car. Both fuel pumps have been changed. The pumps are making a very loud noise and it quit running after 10 min.There also a pressure building in the fuel tank. Can someone give me some advises and suggestions what the problem could be? The engine is a PRV B27.