2008 Buick LaCrosse Super intermittently won’t start

[Jeep7698]

I’m wondering if anyone might have thoughts on this issue. Several times now when my wife has been running errands she comes out of a store tries to start the car and it is completely dead. No cranking.
Other auxiliaries ie., radio, lights etc work fine.
The car always starts at the beginning of the day in the garage. It’s after running for a while that it won’t restart - and that is occasionally, but it sure is inconvenient.
We have taken it to two shops. First one put in a new alternator although in fairness he was not convinced it was needed. The problem reoccurred shortly after. The second shop put in a new starter. Problem has occurred a couple times since.
When the car won’t start my wife opens the hood and jiggles every electrical connection she can see. The car usually won’t start until a couple of minutes pass. The pattern I see is the car starts in the morning when cold and it starts after the hood is open for several minutes after a failed start when driving around.
So, anyone have any good theories I can pursue or recommend to my local shop?

 

[Smith1000]

I haven't encountered this issue on my LaCrosse before, but I did have a vehicle that did something similar and it needed a new starter relay. Just a guess though. Is there a starter relay in a fuse box? The relays usually are not very expensive and are easy to replace.

 

[Smith1000]

Another thing it might be is the cam position sensor. These have been known to be problematic on the 3.8.

 

[HotZ28]

Some things can be heat sensitive on the 5.3L V8, like the MAF, ICM & when they begin to fail, they need to cool down before it will allow a restart. Are there any codes available that might help diagnose the problem?

"The Supers are engineered for Buick by the GM Performance Division to inspire performance on demand. The LaCrosse Super is powered by a 300-horsepower (224 kW)* 5.3L small-block V-8 with GM’s Active Fuel Management technology".

 

[02LTD]

Good catch by HotZ28 in identifying the appropriate engine in the OP’s vehicle.👌

 

[Jeep7698]

Some things can be heat sensitive on the 5.3L V8, like the MAF, ICM & when they begin to fail, they need to cool down before it will allow a restart. Are there any codes available that might help diagnose the problem?

"The Supers are engineered for Buick by the GM Performance Division to inspire performance on demand. The LaCrosse Super is powered by a 300-horsepower (224 kW)* 5.3L small-block V-8 with GM’s Active Fuel Management technology".

Please elaborate…MAF & ICM? What are they?

 

[Jeep7698]

Please elaborate…MAF & ICM? What are they?

 

[02LTD]

Mass Air Flow sensor
Ignition Control Module