Hi looking at this one suffering from surging at idle and under load, has been around abit.
No fault codes, but fuel pressure is fluctating 200-250bar at idle scope also confirms this both the drv and rail pressure voltage fluctuate together as the engine surges.
I know the pressure is low but carrying out a wot see's a very quick response to rail pressure 1.18v to 4.2v 550mseconds.
2.2bar low pressure supply (good flow and fuel) does not fluctuate, I'm probably going to replace the drv as the pump appears to produce hi pressure ok any thought or further test before i replace the drv ? Thanks for looking Martin