Volkswagen Van Stall at Stop

I have a 1981 vanagon and it stalls when coming to a stop. I have replaced the coil, air intake regulator, sanded the grounds, replaced the fuel injectors and had the ECU tested. When it runs it runs well, but after running and coming to a stop it often dies and then is challenge to get started again without opening the trung and disconnecting the hose which allows more air in temporarily. I am stumped and what to try next. Thank you for any suggestions!