My 86 190E 2.3 will not stay running after a few seconds after start up. The Fuel pump is cycling like crazy and the relay is clicking on and off. It sounds like fuel starvation to me. Before this, the car was lurching and the RPM guage will not read correctly, it is pegging with the key on, engine off and swinging all over the place! What the he11 had gotten into this thing? What tells the fuel pump to turn on/off, I am guessing it is a pressure switch of some kind. is the feul pump bad? Any ideas would be great thanks!