I have a 1985 230ce with 252000km from germany. it had starter issues & i now use a start switch to start it. it starts fine runs great for a few minutes then stalls. the fuel pump starts to strugle when engine gets to temps of around 80celcius makes noise then stalls like it cant pump forward anymore. i've replaced the fuel pump, fuel filter, tried disconnecting the sensors on the block. i.ve cleaned the tank & lines. it takes a longer time to stall if the cars on the road. pliz help!?