Low power when cold

Right 94 disco auto it always start straightaway but when put in drive it will not pull the skin off a rice pudding..I have to mount a kerb on my drive and it wont drive over it unless I reverse and get a run at it..At first I thought auto box ..However if I start it and put it into neutral it will not rev above 1100 revs if I keep my foot on the accelarater it will gradually rise in revs..When warm it drives very well although not a speed machine..It feels like it needs advancing???

May be failing fuel lift pump ! Undo outlet pipe from lift pump crank engine see how much fuel is pumped !! Should pulse fuel out at a rapid rate !! A dribble is no good !! Fuel filter should be changed reguarely also!!!

its got new pump and filter first things i changed

Ok assuming your fuelling is ok try checking valve clearances ! All inter cooler pipes! They delaminates internally!!
If all seems ok do a compression test !!! It may be worth removing the top of inj pump to check boost diaphragm !! Sounds a bit like a fuel problem !!! Also check that your turbo waste gate is no stuck open , giving little or no boost !!!

Seems simple, but have a look at the throttle linkage, may of stretched over time

Valve clearances were my problem, after head skim and head gasket, very hard to start and utterly gutless until warm then perfect, redone valves n perfect again, worth checking