injector pump questions power loss

Hi i have a 96 auto 300tdi i have had loss of power problems, anyway tonight started all ok but wouldnt rev and ran real bad, so turned engine off just to think what the hell the problem might be, then decided to start the engine as i turned the key i noticed that normally i have a buzzing sound from what i think is the injector pump but i could not hear my usual buzz, i proceeded to start the engine but had no revs and ran bad. So i turned engine off and tried again this time i had my buzzing injector pump and low and behold i could rev and engine sounded great i got out to have a look in bay , looking at the pump it is supplied by a wire going to 7 pin plug wanting a closer look i gave it a tap and to my suprise the engine tried to stall and again ran bad can someone tell me 1 does your disos pump buzz when you turn the ignition key and 2 are these connector prone to problems 3 or is this controled by an ECU. many thanks

i would say the fuel shut off solinoid is on its way out ? they shouldnt buzz.

when mine is buzzing it starts and runs fine when its not it runs real bad is the solinoid the one with the 7 wires going in from a connecter from the loom

the shut off solinoid has one wire to it and is on the back of the pump.
if you do a search on here for fuel shut off solinoid im sure it has been coverd along with pictures