944 race car stumbles after hard right turns

[race46]

Unless the tank is full the car stalls right after a hard right turn. Many people with the problem have replaced the screen/strainer in the tank and problem solved - I tried that did not help. I checked the vent hose coming out of the sending unit in trunk area. Im assuming the one on the right is the vent hose, pumped some air in the line and had a friend place finger over vent line that goes to charcol canister. Very little air came through and now no air comes through in fact some fuel spit back out of the line.

Any suggestions?