Very often the motor starts but has low power, won't even rev up much. If I shut it off (often it takes two tries) and restart it it has full power. I have changed the filters, hand pump, changed the fuel tank screen and hose but it wasn't dirty) and blown out the fuel lines. Nothing helped. The problem seems to occur more often after I have driven, stopped a while and try to restart it. The problem suddenly appeared more than a year ago but has not gotten better or worse. I have asked all the local mercedes mechanics but no solution. Car has 260K on it and has more power than my 85 300D when running right.