Hello all, I have noticed when my 1999 defender TD5 is driving at low revs, (as in trundlong along in traffic just before you would normally change down a gear) the engine misfires. Also, its not the clunking of the transmission you get when you are in too high a gear. She has a definate, slight missfire, a bit like a petrol engine would, if it had a dodgy plug. If I put the throttle down, the missfire stops. Any Ideas before it gets worse please? Thank you.