It official, I am actually cursed! Lumpy power delivery
Hello all, I have been suffering from lumpy power delivery and juddering along with a fairly good kangaroo impression for some time now. The problem is that from cold in the morning, or after cooling at work for the day, the car runs and idles fine but between 1000 and 3000 rpm it is juddery and lumpy and kangaroos a lot.
I can drive around it by being very gentle with the throttle, and easing it along, or sticking foot to floor. I usually go with the first option to avoid blowing a cold engine to bits by revving it hard.
So far I have changed the MAF sensor for (briefly) a known good one, and then a permanent change to pattern part. (This improved warm response and fuel economy a little, but did not affect the poor running)
I then changed the stat and water temperature sensor for an Alfa original sensor and OEM stat. )This holds a higher water temperature and warms faster, but the kangarooing is still there.
It has been recently MOTed and got through the lambda test and emissions tests with near zero emissions. Lambda value of 1.006!
I have cleaned the throttle body(without moving the flap, just de-gunked it)
When the car is warmed up, the problem completely vanishes and the car pulls like a train and makes no odd noises.
I'm finding it hard to work out as the temperature is clearly a major factor in this. The ambient temp is irrelevant. It happens on hot and cold days alike.
Any ideas as to what the cause could be? My nearest dealer is 60+ miles away and I only have one car.