My son's 2000SLE (my old car) all of a sudden started to stall out when driving.
There was no check engine light and there was no codes or history when we scanned it.
The car is in really good shape and has 270k on it.
Transmission was rebuilt around 40k ago.
It would stall out 3-5 times a day.
This would happen in the city and on the highway.(almost got in an accident a few times)
Again no engine light would come on.
I first replace the MAF and that did not work.
I then replaced the ICM & Coils(OEM) and that did not work.
I thought possible it was the crank sensor but there were no codes to indicate that.
I then did some research and found out a bad ignition switch can cause these type of symptoms.
I replace the ignition switch and the problem went away.($44.00 on amazon)
It is now 2 weeks and the car has not stalled out.
I never realized how important that switch is and the functions it performs.
Hope this helps someone else who might be experiencing this problem.
It is the worst feeling to suddenly stall out and not know when it will happen again.

Glad you found the problem. I had ignition switch issues this past winter. The car wouldn't immediately crank when key was turned to start position. With the key in the RUN position, during the bulb check, the Service Engine light wouldn't be on. Eventually it would come on, fuel pump would prime, and then the vehicle would crank. Did that for 3 or 4 months. Then it started shutting off randomly (and not wanting to crank doesn't make a good combination).
I changed the ignition switch and the security exciter coil (because it was mimicking a security issue). And haven't had a problem since.
I agree that it's counter intuitive the problems changing an ignition switch solves.

Yes it is a good feeling now that the car no longer just dies with no warning.
I did change the security exciter coil last year thinking that was why the security light was staying on.
If you double key it the light stays off.
Unfortunately that did not solve the problem.(I think it is probably the theft module under the dash)
I probably should have changed the ignition switch at that time.
Live and learn.
The weird thing about my problem is that the car would crank over and start up away after it died.

On higher mileage vehicles the ignition switch contacts can simply just get worn down to the point where the conductivity is intermittent.

I had the same issue with my 96 Camaro years ago. It just shut itself off on the highway and wouldn't stay running unless I held the key just slightly past the standard position.

Glad you got it sorted out. It was certainly a huge pain when it happened to me.

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2003 Pontiac Bonneville SSEi (L67) - Galaxy Silver Metallic
1996 Chevrolet Camaro (L36) - Sebring Silver

Having problems with the car stalling again.
Going to try looking at battery.(only 2 years old)
Also thinking it might be a bad wire somewhere.
My question is where is the starter relay located on this car?
Thinking that might be causing the problem.
Thanks.

pass side under hood near a/c service ports.

_________________
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am

Thank you.
Can I assume it is in the fuse box on the front passenger side of the car?

Finally found the problem!!!
It was the CPS (crankshaft position sensor)
The weird thing is that the SES light never went on and there was no codes or history in the computer.
I thought something would have shown up.
Learn something new every day.