Car dies and mysteriously starts back up on its own

pontiac
bonneville

#1

My Pontiac Bonneville keeps dying…at any speed and if, at a high speed on the highway, it will start back up again on it’s own and continue like nothing happened. It will do this once every two weeks or so.



Sometimes, like today, it won’t start back up and will leave me coasting down the highway with no power steering and no brakes. This happened a few minutes after it’s initial dying then starting itself event.



Usually when it dies at a slow speed, it will not start itself back up, but will with my help. It usually runs fine after it starts back up, but today it left me stranded. We towed it home, then it started right back up, ran for a few minutes and died.



Please help.


#2

Okay, I get that maybe no one knows what’s wrong with my vehicle. I went to the Service bulletin website and found dozens and dozens of complaints for the very same thing for the same vehicle. Most said problem unresolved, dealer couldn’t fix…etc.

But one post said
CONSUMER COMPLAINT: ODI Case Number: 856319

Component: ENGINE AND ENGINE COOLING:ENGINE:GASOLINE

Details: ONGOING / INTERMITTENT PROBLEM WITH ENGINE STALLING WITHOUT WARNING. DEALER REPLACED PCM. PROBLEM RESOLVED. *AK *ML

Occurrences: 30 Injuries: 0
Fail Date: 10/15/1999 Deaths: 0
Date added to datbase: 2/4/2000

So can anyone tell me, please what is a PCM?


#3

Powertrain Control Module, or more conventionally, your engine computer. This would be covered under your emissions warranty, which is probably longer than the standard warranty. But if out of warranty, likely to be expensive. The dealership may be able to reprogram the PCM without replacing it. You may also want to ask an independent shop to check their database of service bulletins and hidden warranties for any issues related to this. Those databases are subscription only and may not be covered by a google search.


#4

What year model is it? Automatic or manual transmission? How long have you owned this Bonneville? How long have you had the problem? Have you have anyone locally check it? How many miles on it? Is it up to date for all maintenance recommended in the owner’s manual?

Has it had any CELs (Check Engine Light) If yes have you checked to see what CEL error codes were triggered? If yes tell us what the codes were. The real codes [format (P1234)], not an english translation.


#5

Even if the CEL is not on, there might be a code stored in memory. Some auto parts stores will plug in a scanner and tell you what the codes are for free.


#6

You don’t mention what year your Bonneville is but I had a 98 Olds Intrigue that did this. I turned out to be a bad ground from the battery. It had a very short ground cable that attached only to the fender right under the battery with a 10 mm bolt.
When I got a longer ground cable and attached it to a bolt on the engine the problem went away.