I have this strange problem with my metering unit, when the fuel pressure acuator plug is plugged in (right back hand side of unit) it running like a absolute dog! Clouds of black smoke ect, then when I unplug it, it seems to run perfect! I have changed the wiring loom and it still does it, it's a second hand one I brought for £100 coz my old one was knackered, what is the problem here? Can I get away with running it unplugged at standard boost? What's best to do? And what is at fault here? Please help im stuck on this one.....thankyou