Got a disco 3.9 v8 on lpg, it drives fantastic when moving, however when you slow down typically below 1000 revs it cuts out completely, you have to go into neutral and restart the engine, it restarts on petrol, at 2000 revs the lpg switches in. Then the problem occurs again and again, makes driving smoothly very awkward. Any advise is welcome

Cheers in advance

Rob, Sheffield