1983 gti cabriolet fuel/air problems... PLEASE HELP

Hello everybody i'v recently bought a mk1 gti cabriolet as a non runner, I can start it by lifting the diaphragm slightly and it'l tick over, but when I let the flap down it cuts out. I've checked for air leaks, injectors have been checked, injection seals, re sealed metering head, replaced the fuel filter and still no luck. Before I changed the fuel filter it was struggling to tick over and would not rev up, now it revs up to 3500 rpm but stops there.


Please help I'm desperate for a solution