Wondering if anyone can shed any light on an odd problem with my daughters' diesel G-reg Defender 90. Setting off from home for the London-Brighton on Saturday the engine suddenly and for only a few seconds revved very hard and very rattly with only light if any pressure on the accelerator (clutch down) and the car disappeared in clouds of white smoke - not blue and not a strong smell of oil or anything. We decided to limp the short distance home with embarrassingly large clouds of smoke coming out of the exhaust but over the mile home it gradually got less until all seemed normal. We decided to give it a try and it did the 50 mile journey to Crystal Palace without further incident as well as the run down to Brighton. Then in a queue leaving Brighton in the afternoon it did the same again much to the amusement of the other Landies around us. With the experience of the day before we decided to carry on for a while and sure enough, having smoked our way heavily through Brighton it cleared up and we did the 120 mile road and motorway run home without incident. Oil level and pressure is fine as is coolant. I'm trying to think what would cause the engine to suddenly rev so hard and what is causing the smoke and where is it coming from?
Any answers, hints or suggestions gratefully received.