So I have an '88 VL Berlina with dual fuel, the car runs perfectly on gas and used to run very rough on petrol, but after adding some injector cleaner to the petrol and a change of spark plugs the car will not run or start on petrol, once the engine is running and I select petrol the car runs for 10-15 seconds on the remaining gas then dies. Things we have checked: Fuel pump works (checked by removing the supply and return lines of the fuel rail whilst running on gas, has petrol flow, also can hear the pump running) The gas selector solenoid in the engine bay clicks when selecting LPG to Petrol and vise versa. What we have noticed is when we switch from gas to petrol with one of the injector looms disconnected, our test light doesn't flicker. We have read through countless other posts throughout the internet and have come up with nothing, any ideas on this dilema?