My wifes '03MCS just stalled on her twice yesterday at an intersection and she was not able to restart. After she went back a hour later it started right up. I had the car out yesterday running for 6 hrs and had no issues at all. I filled the tank with fresh 93 before I left in the morning and then she took it in the afternoon.
Today she takes it and the same thing happens. Now she tells me that the 'no start' means it doesn't even crank over. The lights on the dash light up but no cranking at all. This has happened twice in two days. I haven't checked for codes but the no crank has me puzzled along with the stalling.

Any ideas??

Tom in PA

 

I would check and clean the battery and ground connections. Have the battery load tested and replaced if original.

 

The battery is brand new as we swapped engines a month or so. I checked all connections and grounds and they appear good.
I went an retrieved the car at noon time today and it started right up. She said when she was at the light it just died, no warning at all.

 

Sounds like a grounding issue. Same thing happened on my e30 BMW.