My Grand Am is cutting off randomly while driving. I have not been able to purposely reproduce the problem, which makes diagnosis difficult. I am looking for any advice in diagnostics, or parts to test first.
The car will run normally 99% of the time. Without warning, the electrical cuts out and the engine stalls. This has happened at low speed and highway speed, while turning or while going straight down the road. There are no engine error codes, no dash warning lights, and no other indication of what occurred.
After each incident, the car can usually be restarted immediately. Twice, I got a single "click" and no start -- turning the key off and trying again started the car in both of those occasions.
It has been suggested that I check the wiring harness, which I have done by aggressively wiggling and pulling on various engine connections and wires while the car is running -- no results. It has also been suggested that the crankshaft position sensor is faulty or the harness is damaged. Visually, there are no problems with the harness.
The car is not equipped with any remote starter, and does not have any after-market security systems. The stock security system is what I gather to be the most basic one. The security light has never lit, and I am not certain that it CAN light (not used?)
In summary: What should I be checking? Is the crankshaft position sensor a likely candidate here for the problem? I don't want to invest in parts and labor if there's no possible way this is the issue.