Hello yall, Im out in San Diego, got a 2013 range rover sport hse lux 5.0 V8. owned it for 3 years. Never have had this immobilization problem the entire time i've owned it. I am trying to sell the car and wanted to pass smog before I did. I replaced the MAP sensor which was giving me codes that would have prevented passing. Went through a couple drive cycles and cleared up the codes. Passed the smog test. Drove it about 15 more miles then parked it for 4-5 days while I waited for the buyer to collect his money. When I go to meet up with him to sell him the car, it drives fine ( about a 4 mile distance). He turns it on while in park just to hear and feel it again. It shuts down after about 1 minute to a minute 30. I think hmm thats weird, I've never had that happen before, but didn't think much of it. I thought he was taking the key too far away from the car and it was the car natural safety system or something. Then he gives me the money, we sign papers, and he drives away. He then calls me about 10 minutes later saying that it is now shutting down while driving. I meet back up with him and drive it around the parking lot to see exactly what he is talking about about sure enough, the entire car shut down. Total loss of power, no power steering, stiff breaks, everything. Like somebody just shut the engine straight off. no sputtering like the engine was being starved of fuel or air, just a straight power off. I gave him his money back, Got it to o reillys to get the battery/alternator checked and they were in normal good condition. I checked the codes, no codes have popped up. Now every time I start the car up, it will die after about the same minute to minute and a half time frame.

Has anyone had something like this happen before or have any insight on where to start checking or what could be going on here ? My research leads me to believe it could be the crankshaft position sensor but I have not got it tested yet. Looking to do that soon. I am not a Land Rover wiz and am trying to avoid taking it to the shop at all costs.

Summary:
2013 Range Rover Sport HSE LUX 5.0L v8 non supercharged
Car passed smog
car sat for 4-5 days
engine shuts off after about 1-1.5 minutes of it being on with total loss of power
battery/alternator are in good condition
No codes have appeared