on way home yesterday after a 2 hour motorway journey and as slowing down do come of the A1 the car had a slight cough (misfire kind of thing) i wasn't sure if it was me or the car so tried to get it to do it again by dabbing the throttle harshly but it didn't quite do it as severe as it had done, no other symptoms what so ever until today, i made a 30 minute journey this morning and it wasn't until slowing down coming into town it just didn't feel right, like a little bit lumpy on very low revs, then after coming back to the car after it had been sat for 10 minutes i started it up and the tick over sat at 1000 rpm, and stayed there, so i set off home checking it every so often by dipping the clutch and still at 1000 rpm, got about half way back and it got back to normal but seems a little under powered like it takes longer to get going simular to turbo lag, have plugged it in and no codes stored or pending. it's one of those things as the car hasn't put a single foot wrong in 4 years and is completely standard and only done 70k, and seriously well looked after. any help greatly appreciated.