My car is Volvo S40 1999 with 2.0 engine. The fuel pressure is on the idle at 2.2-2.3 bars (should be 2.5) and on higher rpm max. 2.6-2.7 bars (should be 3.0). When I unplug the hose that goes from fuel pressure regulator to intake manifold, pressure jumps to 2.9 bars. I have changed the fuel pump to OE walbro, fuel pressure regulator, fuel filter and injector seals. There is not really a fuel pump relay, but there is a system relay that controls the pump (I think). Also changed that. I have cleaned connectors and fuel lines seems to be ok. None of these part changes have affected anything to fuel pressure. When driving with petrol there isn't really a problem but with e85 injectors' duty cycles become too high on high rpm. On normal drive everything seems to be ok. Any ideas how to solve this?