E30 Zone

I have a problem when i give my e30 m50 about half throttle it stalls but when i let go off the throttle it runs good. I thought it was because i had no exhaust and the lambda was not pluggd in but today when i hade made my own exhaust i tried it but it was the same But i had a exhaust leak between the manifolds and the exhaust can that be the problem?

If you have this problem like me so it can be you have a bad ecu because that was my problem