R129 SL500 jerks in warm condition to complete power loss – what is the cause???

The car has 2 problems. – It only starts when it has been tried 3, 4, 5 times via starter – runs then not bad properly silky even at very low speed as long as it is cold. – as soon as the car gets warm starts to jerk and no gas, then gets worse and worse until that the car takes no more power maybe then still runs on 3 cylinders, then more and more sounds like tractor, no more power assumes, one no more mountain comes up and one voluntarily the Also the ASR always goes on – but was already before – after a short turn off then goes again impeccable WHAT IS THAT ??? Could it be that the kat is closed? Car stood a little more often the last years was also tried with injection cleaner – it was so much better. Nevertheless it was never so bad – vehicle can not be used like this the following has already been replaced: – flammable candles New ngk 6er worth not destroyed – zünkappen, distributor and fingers new however not the bosch but the one from bremi – injection valve all new!