Sounds like your car is having a problem keeping water flowing through the heater core. It could be a stuck heater core valve (part #2 in this image):
Originally Posted by Neotate
After I rev the car a bit over 3000 revs i start to get warmer air
Part Number: 64118369805 (at least for my 2004 330Ci)
Try bleeding the system before you take this part out to examine it.
Last edited by WDE46; 11-29-2012 at 02:23 PM.