Engine turning off by itself

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Hi guys,

The engine in my 2003 Mitsubishi Diamante (6G74) has started randomly turning off.

The occurrence rate has increase in the past week.

It basically turns off as if I took the key out.
It turns straight back on when I restart it.

It does so while driving at times, where it completely loses all power and revs drop, but then turns back on and keeps going (i.e., since it is moving, it essentially jump starts itself). This is felt as a hiccup so whatever turns it off only lasts for half a second or so.

It seems to do it more frequently when idling at the lights and then taking off, though it has happened when cruising in 5th gear as well, and while accelerating too.

Whatever it is, it affects all cylinders at once.
Plugs, leads, filters etc have all been replaced recently.

What could this be?
What should I be checking?
There is no backfiring, would that suggest it is a fuel issue?
The on/off is very sharp and distinct, would this suggest an ignition issue since it is very sudden, both in turning of and turning back on (if at cruise speed)?
 
I believe if that were the case then some of the dash lights would also momentarily go off and back on, but that is not the case
 
Sounds electrical...ignition switch in column/dash has a corroded or failing terminal connection, or maybe even the ignition switch is internally worn so bad it has started to lose touch with other internal pieces,
 
Crank sensor if equiped but I would hang a scan tool, check for codes and monitor live data. Hopefully it will act up while you are monitoring it.
 
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Do you have a bunch of keys on a heavy keychain? See it quite often, the weight of all they keys will be enough to turn the ignition. Try driving with just the ignition key.
 
The car key is separate, so nothing hanging from the ignition.

If it were the ignition, wouldn't the dash lights go off/on as well?
 
First thing I would be looking at is the crankshaft position sensor.
 
Normally the relevant dash lights are off while driving, so you wouldn't see them go out. If it goes off and stays off at a stoplight, don't touch the key until you check if the oil and battery lights came on. They should be on when the key is on but the engine is not turning.
 
The CAS is a hall effect type... from what I understand these rarely if ever fail?


Yes, when it stall the battery and oil lights go on.
But during cruise, it stalls then jump starts itself, but I don't get the normal CEL lights on (as per when the ignition is turned back on)
 
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