Back again with a new series of questions aside from my pervious thread. To update, My husband is working on a 2001 6 cylinder 3.9L Dodge Ram Van that was originally having a NoBUS No Start issue. Fuel pump would not prime on initial key-up and we tracked down the 5v blockage to a tripped ASD relay that had activated after a hit and run accident and or when the starter went out. We replaced the IAC valve, MAP Sensor, TPS Sensor and Crankshaft Position sensor.

After replacing the ASD relay, we no longer have a No BUS code! Yay! The van will start up, but only when the throttle is fully open. The engine runs extremely rough to the point the entire thing shakes and will die and stall out as soon as you let off the throttle. We did just replace the fuel pump, is this a case of too much air in the fuel sysyem? Or possibly gummed up fuel injectors?
​up. Or is is something worse such as timing?

 

There is a valve on the fuel rail that you can connect a fuel pressure gauge to. Doing so and then turning the key to ON to take a reading, followed by starting it and taking a reading should tell you if there is enough fuel pressure to run the engine. That aside, from your description it sounds like some, or all of the plug wires are not going to the correct cylinders. Were the spark plug wires removed at all during all of these recent repairs?