I have recently changed engine of my z but when it deccelerates it stalls or it revs at idle from 200 rpm to 2000 rpm. My mechanic has found that there is no signal going from the ecu to the fuel pressure regulator. When the fuel pressure regulator is given power indepentenlty then the problems seems to stop. (power to it is given straight from the battery randomly). Any ideas why the ecu is not giving power to the fuel pressure regulator? the ecu was fine before engine change. help!!!

May be something to do with the throttle position sensors.

Might need setting up.

The fuel pressure regulator doesn't have a power supply :confused: it only has a vac feed. It does however have a solenoid on the vac feed which does take a signal from the ecu - is this what you are talking about?

Yes that is the one.