Originally Posted by rsnissan

its not the standard pipe..........that has clearly been cut down to feed the Y piece.

Mate looks like your going to have to do this systematically

I would 1st check the voltage to the pump get someone to sit in the car with a multimeter connected to the pump and then see what it reads when the problem occurs.

Then simplify the setup i.e remove the y piece and just to to the 1 pump and out of the one pump to the fuel pipe.

and go from there possibly with the aim to dropping the fuel lines, tank etc so you can eliminate that line of enquiry at least.