Hi I have replace petrol pump, filter and plugs on my Golf gti 1.8 engine and air filter as well I'm trying to start de eingine it start and stall for about a minute what could it be the problem

I would hope u have an engine code related to the problem. Retrieve the codes that's a start. There a many components needed to start the engine those are about 2%

Ok am not that sure about codes but what I did is at first I took out the engine that came with de car I then put another engine but I didn't change computer box I used old computer box with another engine (new one) but I didn't connect the computer box that came with it then I drove with it about 230 km then it started to give me this problem of start and stall so what should I do in this regard

start checking vacum lines also make sure you reconnected all the harness tightly