What causes the pickup to die while driving and how can I remedy the problem?
There are many things that can cause this to happen. The most common cause would be running out of gas. Even when the fuel level sending unit is sending a signal to the dash displaying the tank is 1/4 fuel, it may not.
The best first course of action once you have determined there is fuel in the tank would be to check for any stored diagnostic trouble codes. These codes will help pinpoint the issue. Should save lots of time and money if you approach the problem this way. Beats throwing parts at it.
Another thing you can do if it doesn’t start right back up after it dies is to look for what the engine is not getting. Spark, fuel, etc.