My 2006 F-350 cc srw 6.0 has cold air intake and 4" turbo back exhaust. It currently has the stock Ford tune. Yesterday towing my 7000 lb. trailer over the altamont (medium hills) the c.e.l. wrench appeared on the instrument cluster. I pulled over and turned the truck off before I hooked up my sct tuner to check for codes. No codes stored and pulled fine for another 100 miles then wrench came back and cut power. Egt not getting over 1100 f. Any ideas? Once truck is turned off, it clears light and goes back to normal.