Help needed with my 914 2.0 fuel injection. I have just put this engine back and fitted stock fuel injection, it started up first time and ran fine, but did not idle that well, but great throttle response etc. I had to split it again to fit a back oil seal, and then adjusted valves and fitted new rocker cover gaskets etc, now since that, when I start it up it will run for less than 1 min and then begins to splutter and dies. It will take the throttle and rev in that timeframe but it has me baffled. It has new points and plugs, new/good hoses, good distributor.
Does anyone have any advice on where I might start, as this looks like a
slow elimination process.
Any help/advice greatly appreciated.

1963 Karmann Ghia LHD. Sold
1969 Porsche 912 LHD
1973 Porsche 914 Almost RHD.Sold
2005 VW Caddy TDI.
1959 Porsche 308 Super.
1982 mk1 Golf TDI.
1983 Toyota BJ40 Landcruiser,