Every so often my 1996 E 150 will sound like it want to die. Often in traffic and when it is warm usually. Putting it in Neutral at a light will help. It will then just snap out of it. The problem was very bad going over a pass in the Rockies but I made it. It does not happen often and if it gets to bad a short rest will cure the problem.

I have no idea what to look for. Any ideas?