Well we've been having another look at the car in question today. Definitely got all the spark plugs in the right holes. Checked for any dislodged hoses/electrical connections, found the capacitor going to the coil was disconnected, but this didn't seem to affect things anyway. Only unaccounted for double wire is a black wire and orange wire in a rectangular connector at the back of engine bay. Lost or surplus? (this is an auto tranny) One other strange point. The fuel adjustment screw has been blocked off. Is this normal on twin turbo setups - anyone? Apparently this needed to be drilled out on the fresh-from-the-factory engine (this engine has 34000 miles on it!) Idle speed switch is ok. In fact, the only time the engine will run is with it pressed! Just to clarify a bit more what the engine is doing. The engine seems to idle quite nicely, although it doesn't hunt properly. When any throttle is applied it coughs splutters and attempts to stall. Also when throttle is applied the airflow sensor oscillates rapidly, and it misfires badly. With the engine off, the metering head plunger comes back with quite a spring when you push it down, unlike Martin's one which bounces nicely against the rubber endstop as the plunger drops down slowly. Control Pressure regulator has been reconditioned. Could it be the metering head at fault?? Any other ideas? Thanks Richard #2727