Saturn gurus, what's wrong with my SC2?

[War_Wagon]

1998 SC2 automatic, the car runs great 99% of the time. When it's cold though, if I just get on the throttle lightly from a stop it stumbles, almost like it's out of gas. It does it a little bit when it's warmed up, but it's really bad when it's cold. Last night I pulled out into an intersection and it actually stalled, that's the first time it has been that bad. 144k KMs on the car, no check engine light comes on or anything, and like I said the rest of the time it runs fine. Any ideas?

[baldlobo]

changed your air filter?; could be your fuel pump(pressure test); vacuum diaphram in the fuel rail(don't know if your's has one of these).

[War_Wagon]

Just an update in case anyone else is in the same boat with their Saturn. The stumble continued, then a few days ago it started to get hard to start when it was cold. Coolant temperature sensor was the culprit. It's common on Saturns from what I have read, but usually the symptoms are hard starting when cold, I guess the weird stumble off idle I was getting was the earlier indicator. The end of the sensor cracks and messes with the readings. Sure enough mine had a big crack in it, $12 for the part and 15 minutes to replace it. There is a great how to video on youtube, it's a simple job but it's always nice to watch someone else do it first

http://www.youtube.com/watch?v=cucm7QGlsYs