1989 4.0 dies after start up. About 10 seconds. When I disconnect the Vacuum line from the MAP sensor it starts hard but will run. If I reconnect It dies immediately. Replaced fuel filter, MAP sensor, plugs, dist and rotor, some vacuum lines and the air cleaner. The plugs looked black like too much fuel. I do not believe it is the fuel pump or rail because when it is not connected to the Map sensor it will run and drive. But very hard to start.