Hi...I have a 2002 Defender TD5 (110,000 miles) Recently I started to suffer from loss of power/running rough/uneven when the engine had to work hard ( ascending steep hills etc) I took it in to my 4x4 mech ( mainly Land Rovers) Nothing registered on the dynostic's but discovered the air flow meter was faulty & replaced. Car run a lot better ( more responsive) All was well untill after a run of 78 miles of motor way, started to climb a hill & the problem returned ! After pulling off the motor way,switching her off for a short while, all was back to normal !...Any ideas what could be breaking & then rectifying itself ?...Thanks Russell

good idea to use the intro page first Russel,you might get more responses then

Sounds like overboost.... Check your wastegate does it move ?

Vacuum in the fuel tank?

Shifty1962 said:

Vacuum in the fuel tank?

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Yes, I'd think about some sort of fuel supply problem. Once it's been standing for a little while it gets a chance to catch up. Could be anything from a low fuel level in the tank to the pump getting tired and not delivering at full pressure, some sort of blockage (the mesh on the bottom of the pump sometimes clogs up with debris) the filter, the pipes (some models have little strainer filters where the pipes go into the filter block) or a fault with the fuel pump relay. I could change the engine revs by waggling the pins on my old one. There's also the fuel pressure regulator, but you don't hear about them malfunctioning too often, just leaking.