Originally Posted by DazC

On the electromagnetic fuel pressure actuator on the side of the metering unit (rectangular device with a 2 way plug, usually either black or grey, held on by 2 or 4 screws, I can't remember), there is a screw on the face of it that is flush up to the metering unit body. Remove the electomagnetic actuator and then remove this screw. Underneath the screw is an allen key. Adjust this (can't remember which way to adjust it. One way will weaken in and the other will richen it) and take it for a run. You really need AFR equipment though as you could cure your problem but still be running dangerously lean.

You may also have wiring issues to your fuel pump of a blocked fuel filter.