Need help with 2004 Grand Prix stalling

[robsmo]

I have a 2004 Grand Prix GT2 with just under 60K on it (hey, I didn't buy it to let it sit in the driveway!).

Upon starting the car, it intermittently stalls after about a second. It seems like it's going to start for about a half second, idles rough breifly and stalls out. It doesn't happen everytime I try to start it, but i can't seem to find a pattern. One thing I know: when I press the gas pedal and rev it on startup, it always seems to work....but I'd much rather have the car starting on it's own merit.

My mechanic told me the diagnosis itself could be expensive, so any help would be greatly appreciated!!

- Robbie