Grand Vitara. Not Starting. Fuel Managment/Delivery issue.

[Georgec44]

My Grand Vitara 2.0 16v 5dr (06) recently had it's gear box replaced and ever since then it has developed an intermittent starting problems. It turns but it sounds like there's no fuel. When you plug in an diagnostic or OBD Reader it doesn't spit out any error codes, and the car starts. I'm guessing it has to be something to do with the control box and the fuel delivery/ management. Once I start the car with an OBD reader plugged in it starts and drives absolutely fine. Has anyone had this before or can anyone point me in the right direction to get it fixed because it's at the point that I've lost confidence in the car. Any help or advice would be appreciated. I'm in the UK near between Reading and London. Thanks