Have a 2002 Yukon 5.3 ltr engine (155K miles) that likes to cut off at highway speeds. Usually happens after 4 or 5 hours of running at 70 to 80 mph. Strangley if I set the cruise control and do the same speeds, nothing… When it happens I end up coasting to the side ot the roadway and sitting there for 15 or 20 minutes and it’ll start right up and usually go the rest of the way. I’ve talked to a couple repair shops and they have checked service bulletins and have never been able to find anything. Will be driving to Connecticut for the 4th and not looking forward to being on 95 with the possibality of this happening agian. Any ideas??
Possibly a bad crankshaft position sensor (CKP). These tend to fail sometimes when they get hot. The signal from the sensor cuts out, and the computer shuts the engine off. Then when they cool down they start working again. Try replacing the sensor.
My guess is that you’re either experiencing something getting heat soaked or developing a vacuum in the gas tank that’s making it difficult for the pump to draw fuel. If this does happen again, try removing and replacing the gas cap. If this works, you have an EVAP system problem.