1989 Volkswagen Cabriolet fuel pump whines front end jolts

1989 Volkswagen Cabriolet mileage: 130,000. Manual shift. Frequently after driving in stop and go traffic or after prolonged periods of driving, the fuel pump begins to whine noisily. Shortly after that, the front end jolts violently a couple of seconds after being shifted into another gear. Frequently after that, the engine stalls. The car starts easily after it stalls, but within a minute I'm in the same boat. The fuel pump has been replaced twice on the advice of my mechanic and the engine mounts have also been replaced, but I still get the same symptoms; whining loudly before the jolting and stalling. The whining and stalling leads me to believe it's a fuel pump problem but the front end jolting makes me think I may have to replace the clutch also. Any suggestions?