NEW TO ALL THIS!
Im after some advice , my daughter has a audi a3 (bkd)
unfortunately the head gasket went and boiled over several times apparently after constant top ups.
and also cutting out when driving....

Ive replaced the cylinder head gasket with new bolts.
fitted new cam belt kit along with water pump.
also full service of engine (found black fuel in filter) replaced tandem pump.
flushed fuel tank out
fitted new lift pump unit in tank (blocked)
fitted new cam shaft sensor.
fitted new egr valve at manifold end .
stripped and cleaned rear egr control valve and tested heat exchanger.
stripped turbo and cleaned vanes (variable vanes jammed).

ive only got snap on diag to test cleared all errors.
started car ran several times on tick over sometimes upto 30 mins plus
drive 500 yards down the road no warnings on dash engine dies?
get it towed back turn key several cranks starts left on tickover all ok only when I take it down the road it cuts out and refuses to start
anybody got any ideas?
ive spent days on this trying different things and ways also costing a fortune.

thanks in advance