Stalling in stop and go traffic.

[LMS]

My 2005 Bonneville SE stalls (after first seeming to lose power over the steering and brakes) for about 10 minutes when out in stop and go traffic. Down here in Atlanta, it's hard to avoid stop and go, brake-slamming driving. The ignition won't turn over for about 10 minutes and then, suddenly, the engine turns over and we're on our way again!

My SE has only about 120K miles and was as reliable and reasonable as could be, until she wasn't.

I've spent a year and some expense to have just about everything flushed and replaced, and yet the stalling continues, despite mechanics' assurances that they've remedied the issue. There are no leaks, and have never been leaks.

Thinking I was doing right, I was using premium gasoline, and now know that's wrong. I promise I will never do it again. Have I damaged the car permanently by doing this?

Do you think it could be something as simple as a flawed vacuum seal? Wouldn't the mechanics (3, to date) have found a flawed vacuum seal.

All guidance is greatly appreciated. I don't want to part with this old friend.

[dougtoth]

Is the SES (service engine soon) light on?
Are there any codes in the computer?(AutoZone or O'Reilly will check it for free)
Could be a couple of things causing this issue.
One is the ICM(ignition control module) which is the part under the 3 coils.
Also could be the CPS(crankshaft position sensor).
My son's car was having similar problems.
It turned out to be the CPS.
Good Luck.

[imidazol97]

The ignition won't turn over for about 10 minutes and then, suddenly, the engine turns over and we're on our way again!.

Clarify what happens:

Are you saying the engine won't even crank when you turn the key? It won't even rotate?

Are you saying the car does crank over but there's no firing like it's trying to start? It just cranks without firing.

And you mentioned the power steering and brakes... are you saying they don't feel right when the car is getting ready to die? The steering is hydraulic and the power assist if the engine is stumbling may feel abnormal.
The brakes are vacuum assisted and they should feel okay even for a press or two after the engine stalls.
Can you elaborate on that a bit?

[96 SSEi]

I would inspect battery and connections

[LMS]

Hi imidazol97,

Yes, the car would crank over like it was trying to start, but wouldn't fire for several minutes. Then, suddenly, it would fire. And, I was on my way again.

And, you are correct in your description, the power steering and brakes didn't feel right when the car was getting ready to die..... I would press the brakes to the floor, and the steering seemed as though I was gone, so that I would force the wheel so that I drifted to the side of a road, where the car then died, for awhile.

The brakes may have worked after the engine stalled... . I never thought about that, but now that you ask... I kept my foot on the brake while cranking the engine, and, by then, the brakes were no longer flat on the floor, so the brakes were, indeed, functioning once the engine again turned over .

Hi 96 SSEi,

Thank you for that. Apparently the battery and connections are good. I had the battery and the spark plugs looked at.


Thank you, all.

[96 SSEi]

you can try unplugging the maf sensor and see if anything improves.
when you lose power, you will have essentially manual rakes and steering to coast to a stop so, you will have considerably more brake pedal travel to haul to a stop.

[LMS]

Thank you all!

A broken crankshaft sensor has been detected and is being fixed. Do you all think that this will remedy the problem. In other words, does it seem reasonable that a defective crankshaft sensor would cause the stalling and temporary loss of power steering and brakes?

That little Bonneville has been like a loyal friend and I want to do right by her.