Challenging problem

I am struggling with a problem on 2005 Passat project car. I did a trans swap and rebuild the engine. The car starts and runs fine for while. Out of the nowhere the engine cuts out and its almost impossible to start it again. After a bit the engine does starts but cut out at higher rpms. There is no engine codes associate with the problem. It sound to me like a speed sensor problem? but no code generated. I disconnected to throttle valve just in case in was closing intermediately no change. Is it possible I am loosing power to the ECU? Is there a relay that could be failing?

I have a malone stage one tune and the manual trans software upgrade.

ANY suggestions? thank you for reading.

I had a somewhat similar issue and it turned out the fuel pump relay was intermittent. After it stalls, if you turn the key off and back on, can you hear the in tank fuel pump humming, as it starts up? If you hear nothing, its either the in tank pump, or the relay.

The relay is shown here , There is also a second relay in the ECU that is upstream of this one.: http://forums.tdiclub.com/showthread.php?t=245377


Also possible that the tandem pump is bad. stalling at higher rpms would be because you do not have enough fuel.

Before you do any of this: Could your fuel filter clogged?