I'm assuming no trouble codes are set (service engine soon light is out).

It takes four basic things for an engine to run: fuel, air (actually
oxygen), compression, and spark. Air is unlikely cause here since this
surrounds us everywhere and there is not much to the air intake system. The
fact that it runs normally "sometimes" kinds of also rules out the
compression angle as well. So its either fuel delivery related or spark
related. Determine which is missing and start your troubleshooting from
there.

I have used a spray can of starting fluid down the throttle body to see if
it would start ... if it does then dies, look at the fuel system: dirty
filter, defective ASD relay, defective/dying fuel pump, other? If no change
and still won't start with fluid, then remove a spark plug and while
grounding it to the engine using a rubber glove as an insulator, see if you
get spark while someone else turns the key. if no spark check the
electronic sensors, probably the crank sensor or the computer module. Also
make sure the battery is good and all cables and grounds have clean and
tight connections since electronics do funny things when battery is low or
there is a bad connection.

Also, get a Factory Service Manual for troubleshooting since it has
schematics.

Bob

"cdiesel77" > wrote in message
oups.com...
> Hi,

> I have a Saturn SL2 about 128644 miles on it and my question is what
> can cause the engine to just stop while driving or just idling in the
> driveway. At first my girlfriend would be sitting at a drive thru or
> at a stop light and the engine would just quit on her. She would have a
> hard time starting it right after so she would have to sit there for
> about 2 minutes which then the car will restart with no problems. A
> week goes by and it did it to me but even after waiting 10 minutes it
> will not start. Friend told me i had faint spark but he got a spark
> and it started up right away. Then died shortly again but started up
> again and then no problems at all. Now if i start the car and let it
> sit in the driveway for about 5 to 10 minutes it just comepletly shuts
> off, and wont restart until i leave it alone for about 25 minutes and
> repeat problem. I have new Ignition Module and coils. new spark plugs
> and wires. Replace the ECTS sensor. Clean the EGR Valve to the best of
> my Knowledge. I dont know what else could be killing my car.. PLEASE
> HELP!