whats wrong with my car automatic s reg volvo v40?

firstly was sluggish in the morning. engine started well then when took foot off gas to stop at junction or slow down to turn corner there would be delay in accelerating of 5-8 secs. once travelled about 1 mile or less car is fine

last few weeks starts well first problem persists. but when engine is turned off to stop after 1 mile or 40 miles when i restart the engine within 0-3 hours the car judders when stationary and when the foot is on the gas the car goes very slowly and with foot right down on the peddle wiil build up eventually to 30 miles an hour over a first 1-3 mins if i need to stop at a junction or roundabout the same thing happens. occaissionally if i am on a run and i dont have to stop it kicks into action and its fine again but this not ussual. when this happens the rpm are 30-40 but the speed does not reflect this and there is a horrible smell in the car but not under the bonnett? what can it be? i am waiting for a lease car and will be imminently ready.I use my car as jo community based: reluctant to spend any more money on it if poss. thank