1996 Ford F-250 just dies

This has been doing this for about a year just got a lot worse the past month. The truck will just die does not mater what the conditions are, warming up, driving at any speed, stopped at a stoplight/sign it might start right back up or take up to 1 1/2 hour no warning no nothing just dies The only thing I know is there is no spark when it dies so I know its not gas. Someone told me might be computer