Was towing a load of hay the other day and all of a sudden the truck seemed to defuel. Noticed the red lightning bolt was on then went off and it started acting right again. It has only done it when towing heavy but unloaded everything is fine what gives

 

sounds like a fuel issue. whats done to the truck? weak fuel relief valve?

 

Everything is stock just have the egr unplugged

 

I had the same thing happen so took back to dealer and it was a switch on the brake peddle that senses position between throttle and brake peddles, not a big deal and if you throttle is depressed and brake is pressed at same time or moved enough by moving feet around it senses a throttle position error,the same thing happens if you try to power brake