Reda Otroch

I have Mercedes E300 1991, I had an issue before that my car it take a long time to start when the weather is cold and it was too, so I replace a sensor for that I don't know what is its name, then it is fine but it still shuts off sometime when the car will run and ABS light always on.I checked it, it was from OVP relay I replace it with new one everything is ok but later on it still shuts off in sometimes upon starting to move back side when i have low fuel and the engine not 100% stable it is feel like ----|-----|------|---. any one know what will be the issue and how it will solve