All other times the truck starts and runs great. However if it reaches freezing or below it just won't start. I have cranked on it for 15-20 minutes before it begins to sound like it is going to start. Any ideas??

This link should help:

https://www.askmehelpdesk.com/cars-t...ml#post1415281

. Remove both batteries and fully charge. Most auto parts stores will do this for free.

. Ensure the glow plugs work properly.

. Change the fuel/water separator filter, if it hasn't been done recently. This link will provide additional insight on diesel fuel when the temperature drops:

https://www.askmehelpdesk.com/cars-t...ml#post1985158

. Use SAE 5W-40 full synthetic HDDO, since diesels are cold running beasts.

. Install an engine block heater, if the problem persists.

This is a gasoline engine... after you get it started (if you do) it will run well and restart until it gets really cold again.

Sorry, I assumed you had the 5.9L Cummins diesel, which I had been working on during the day with a Texas disaster response team.

. Check/replace the Engine Coolant Temperature (ECT) Sensor, which affects fuel injector pulse width. The ECT Sensor is a temperature dependent resistor (thermistor), whose resistance decreases as the engine coolant temperature increases. It provides a richer mixture when cold, leaner mixture when hot. They become corroded, due to not changing the coolant frequently enough, flood the engine, and waste a tremendous amount of fuel.

. Use SAE 5W-30 full synthetic engine oil (e.g. Mobil 1 or Pennzoil Platinum).