Was the tank low on fuel? I know that the gauge unit is in the back of the tank. Going downhill, my 4Runner can read empty. Then on flat ground 1/8 tank. Uphill, nearly 1/4. The gauge is clearly reading off the back of the tank. If the actual fuel pickup is located in the middle and you are on a decent hill and low on fuel, it might putter out... Just throwing out the obvious.
fuel pickup is in the center of the tank
![Yes Nod :yesnod:](https://board.marlincrawler.com/Smileys/marlin/yesnod.gif)
This could be the problem, but I doubt it. Unless she is on E, there is enough fuel in the tank to keep the truck running on an incline.