What's causing my car to mysteriously stop running?

Hi.

So, I’m driving my 2003 Saturn LW 300 wagon (3.0 liter, V-6 engine) the other day, and the engine shuts off out of nowhere. Luckily, I was on a quiet secondary road, so I drifted to a curb in neutral. Then my car wouldn’t start. Eventually, my car started. I drove for another five minutes, and the engine shut off again–without coming back on–while I was driving. This time I couldn’t get the car started again. I had it towed into a shop. Of course, the car starts up, no problem, in the garage. But while it’s running for 20 minutes, the engine cuts off once again. They started it back up again, and it ran without stop for 40 minutes. The mechanics can’t figure out the problem, and I don’t feel real good about taking this car back on the road, especially since I do a lot of highway driving.

Can anyone offer some possible thoughts about what’s going on here? (A friend’s father had a similar problem with his truck; after taking it to four different shops, one of them finally determind the problem–the fuel pump’s electrical harness. Is it possible I’m having the same problem?)

Thanks in advance for your help!

My best,
Andrew

Saturn’s have a history of the problem being caused from a defective Crankshaft Posistion sensor.

This sensor informs the computer whether or not the engine is rotating. If the signal is lost from this sensor, the computer see’s no reason to no longer operate the fuel/ignition system and the engine shuts off.

Tester

If there are no codes stored and the problem is not the crank sensor then there’s the possibility of an intermittently failing fuel pump.
A pump can come and go for an at will until at some point it dies and stays dead.

This can be even more prevalent on cars in which the fuel filter is not changed regularly as a partially clogged filter may allow the engine to run fine but will put more strain on the pump which in turn shortens the pump life.

If the engine shut down while it was at that shop and they can’t figure it out, you should consider taking your car elsewhere.
It sounds like these guys may not have the expertise or equipment to fix your problem.
Has the shop pulled any fault codes, checked fuel pressure, etc.?
Are you already big bucks into this?

Agree with the above comments.
I have a 2004 LW w/ V6 and while I haven’t had the problem you describe, I’ve noticed in a few of the Saturn forums I’ve visited, that our L-series seem to have a problem with their original fuel pumps, so if there aren’t any obvious codes, check the fuel filter and if that’s clean, your pump is likely failing.
Also, by way of a cheap fix, you might try an octane booster if you suspect bad fuel.
Good luck and please let us know when you find a solution!
JP