Guten Tag, I have a 1989 Mercedes-Benz 190E 2.6, with some 160 thousand miles on it. I don't know how long the problem has been occuring, if it was progressive or if it was more instantanious. In any event, the basic problem is that if I press on the accelorator after coming to a stop the car hesitates as though it is not getting enough fuel. If I am on the highway and I floor it I get the feeling that it is not getting enough fuel as well, and if I back off the pedal I get more power. It also idles rather low, and when put in gear the idle becomes progressivly lower. I have removed the air flow sensor, and given it a through cleaning, replaced the fuel filter, and the cap, and the roter, and the plugs. If I disconnect the idle air pump it idles higer, and than if I reconnect it while the car is running it dies. But I can instantly re-start it. Currently I have the cable for the accelerater adjusted so that the idle switch is not contacted, and the car runs better. I hope I have provided enough information and I hope that someone can help me. My next ideas are that the over voltage protection relay may be to blame, if I shake it, it rattles. But the car runs without it connected.