2003 GrandAm stalls while driving-HELP!!

:banghead: My 2003 GA (36k miles) stalled while going 70mph on the hwy yesterday. But then started right up. Later in the day, it would crank normally, but didn't want to turn over. Finally did, then it didn't want to start again later that night, choked and sputtered, then finally started. Then stalled again while driving on a side street. It makes no noise when it quits, no lights come on, no check engine light so no codes can be read. It just shuts off, as if I turned the key off, but the headlights, radio, etc., remain on. And of course I took it to the dealership today, it didn't malfunction at all, and they could find nothing wrong. I just bought it less than 30 days ago. I am trying to get them to figure it out while still under 60 day warranty, but I'm not having any luck. I think we'll be troubleshooting this one ourselves. Anyone have any suggestions?

Welcome to AF.

So what size engine?

When you say "it would crank normally, but didn't want to turn over" that is condescending.
Because if it cranks, then it is turning over,
just thought we should clearify that.

So its cranking over , It just doesnt fire up when cranking?

When you get a no start you need to check for spark at the spark plugs.
Then check to see that you are getting fuel.
Do you here the fuel pump running when you get the no start?

Sounds like an ignition system problem to me,
just dying at random.

Has it been checked for trouble codes when it doesnt start?
You can still have DTC and get no SES or SVS lights. :grinyes:

Might try replacing your fuel filter too.
If its partailly clogged it'll choke the engine right out.

:banghead: My 2003 GA (36k miles) stalled while going 70mph on the hwy yesterday. But then started right up. Later in the day, it would crank normally, but didn't want to turn over. Finally did, then it didn't want to start again later that night, choked and sputtered, then finally started. Then stalled again while driving on a side street. It makes no noise when it quits, no lights come on, no check engine light so no codes can be read. It just shuts off, as if I turned the key off, but the headlights, radio, etc., remain on. And of course I took it to the dealership today, it didn't malfunction at all, and they could find nothing wrong. I just bought it less than 30 days ago. I am trying to get them to figure it out while still under 60 day warranty, but I'm not having any luck. I think we'll be troubleshooting this one ourselves. Anyone have any suggestions?
Could be alternator, fuel pump, or crankcase sensor