I have a 2004 BMW 325I that keeps stalling and

oh dear, this sounds like bad news,,, it could be the torque converter starting to sezies up on you but at the bmw has whats called a "stepper motor" to ajust its throtol settings there is little you can do to up the tickover speed a bit,,, it should be ticking over at 750--850rpm in gear when hot,, if its not then its ticking over far to slowly and it will keep stalling on you when you try to pull away or are sat at the lights wateing? putting it on a computer is the only way to ajust the tickover