Another stalling X5

[jabba]

Have read so much about stalling X5's at low speeds that my head is going to explode!

X5 3.0i Sport E53

Just wondered if anyone can shed any light on my situation. Symptoms are, car runs ok until coming to a stop i.e. junction or slow corner, rev counter will undulate up and down and sometimes, if it's really bad unudulating, it will stall. Car starts right back up and off I go again.

(If revs start undulating and I put it in to neutral then the revs stop undulating).

Have so far changed the idle control valve and DISA valve. Have cleaned the MAF sensor although have read that it could be this at fault although at £240 I would rather have a better undertsanding of whether it could be this.

From the engine bay with the hood lifted, I can hear a loud sort of suction noise like air being forced through something or into something. Don't know if this is normal or not

I put the reader on the car today and it came up with two errors relating to "oxygen sensor adaptation limit reached Cyl #1-3" and "Catalytic convertor efficiency, Cyl #1-3. Have reset these codes and will see if they come back.

Sorry for the long post but before throwing more money at it thought I may try and get some expert advice before sending it to the indy for a thorough check.

Many thanks.
jabba