I recently bought my P38 4.0 lt HSE with LPG conversion and am bitterly disappointed with its performance. At normal driving it appears fine but under hard accellerating or under load on a hill it has a severe flat spot in the rev band around 2700rpm. If i kick down hard it does respond but as it auto changes up again it again loses power. I bought it to pull my caravan but on a recent trip at the first sign of a hill or a motorway incline i lost power so much that all the trucks were overtaking. It does this on both petrol and LPG. I have read that this is one of the problems that RR's have, but can be overcome by buying a different chip and / or remapping. The cost of this I believe is around £850. Is there an alternative or some other solution or suggestions. I cannot accept that this is a symptom of a V8 powered Range Rover.