I have a friend that has a E350 that has been sitting less than a year that they are trying to get going again. I have not actually seen the truck yet I am going this weekend to look at it but wanted some ideas on what it might be.

It is a 1998 E350 old bus, Gas, Automatic, I believe it to be a 5.4l and an 4r100? From what I have seen these are the only options for gas in this truck.

It starts and runs well Idles well in park and in Neutral. When gear shift is changed from either of these it dies and the instrument panel goes dead. Turn it off and back on and it will start and run in Park or Neutral.

Any Ideas on where to start on this issue?

 

I would start with checking the grounds, that can make a vehicle do strange things.