2012 Yukon XL. Stopped for gas near the Canadian NY border. After filling.... absolutely dead no electricaL power. Was able to start. However when getting back on the highway the door locks fluttered rapidly up and down and the dash lit up and gauges fluttered. The tach revered up with no power. I was able to limp along at 20mph on the shoulder. Eventually was able to reach 50 mph. Yes I thought it was a grounding issue. In Canada I redid/cleaned all the grounds I could find. The worst location was the one going from the negative post to area under the front bumper cover. Not sure of the one behind the driver side A pillar ? All appeared good, but the neighbors code reader said misfire # 2. Redid all the coils,plugs, wires last year. Had some spares so was able to get back to Maryland. ??? Was driving on misfire damaging other plug,coils causing the system to go into a limp mode ?
Should note I was pulling a 12' trailer containing a full 12 drawer snap on box. I know. I should have opted for the 6.0 motor. Thinking about the new 6cyl diesel.
Maybe buy a lotto ticket.
