2000 Saturn SL2 engine dies often but can be restarted

My Saturn engine dies more and more often. It happened starting around one
year ago when I waited for a traffic light. I had to restart it. And then,
the engine dies more and more often. Usually, it happened when I made a
turn and waited for a traffic light. These days, even during driving on
highway normally, the engine died sometimes. However, I can always succeed
in restarting the car (sometimes I had to turn the key several times).

A mechanic checked my car, replace the four starter plugs and fuel filter.
The problem wasn't fixed. I knew that catalytic converter of my car was
also broken. The mechanic told me it could be the problem of "catalytic
converter". But I am wondering "catalytic converter" can cause engine die
during driving.

I do greatly appreciate for any advices or possible solutions to this
problem.

Thank you very much in advance.

 

If there were a "Saturn FAQ," this would be one of the top few entries.
If you do a Google groups search (http://groups.google.com/) against this
newsgroup (rec.auto.makers.saturn), you'll find many, many articles dealing
with engines dying and/or revving low.
IIRC, Coolant Temperature Sensor and fuel problems (for example bad gas,
bad fuel pump) can cause these symptoms. Hopefully, others with better
memory and/ or more experience than I will happen along and provide more
useful information.
Good luck!

 

Well, it seems to me there are many possible cases. I will try some in this
weekend and let you know how's going.

 

I'm coming back to report the result. I fixed the problem which was caused
by EGR valve failure. I tried to clean it but after a while, it failed
again so at last I bought a new one and then everything was perfect.

Thank everyone here. I got many useful advices.

Good luck.