Tuning Strada start but idles rough then engine dies

[Strada1979]

Hi guys

I need some help please

When i start my Strada it starts and idles very low..about 300-400 rpm and splutters.
When i step on the gas pedal it immediately dies on me...

I checked the usual suspects namely fuel,spark ect
All in place...

I replaced a fuel pump relay yesterday as i did not get through any fuel...after that the car started fine...

Now today i have this issue...
What i must mention is that when i took the fuel tank off i broke the return line connector on the fuel pump housing ..that was repaired and i put everything back together...

Bit now after all off that.....the starting up is given me hassles....

Any advise
Thanks
Johan - South Africa