Someone resolve this problem ? The same situation here in w140 500SE 1992. m119.970
When car is cold run perfectly, stable idle, good acceleration no missfire no backfire. When it getting 80C then start to missfire engine shaking and finally dies. After that i cant restart it. Car is crank but backfire to the exhaust so fuel is leaking. I thin i s not fuel pump problem becouse i checked fuel pressure and it was 3.5bar on idle and 4.0 bar while accelerate. I changed almost everythin: CPS, Cam sensor, O2 sensor, 4pin coolant sensor, Used EZL, Caps, Rotors, Fuel pressure regulator, clean injectors, are vaccum and breathing hoses, intake manfiold gaskets, engine/lower wiring harness, Used base module. I think about LH module and MAF. Please any advice can help. the car is using only in weekends but the problem wasnt occured before. I found lot off posts about it its common problem but finally unresolved.