BMW Repair: 2001 325ci idle problems, bmw 325ci, vent valve

Question
hi, i have a 2001 bmw 325ci with 130k, all highway mile. lately i have had some problems with the idling of the engine, this is what happens, when i start slowing down lets say from 30 down the rpm guage drops from 1.25 all the way to .5rpms and its not a slow drop its a very rappid drop, and after it drops it starts jumping untill the car finally stops is when the rpm guage fins a resting place, this happens all the time, and also when this is going on the mpg arrow when im slowing down goes all the way down to the left side like im not using any gas like its suppose to, but then at a certain point of me slowing down it jumps up to 20mpg and then back down to its resting place, it also feels like there is low in tourque after 2 rpms like you have to press on the pedal more for the car to go faster. its really frustrating, the check engine light isnt on. please help me figure out whats wrong with my beamer.

Answer
Vitaliy, I would look at the idle valve just above the throttle body and the rubber intake duct boot that goes on the throttle and idle valve for tears letting unmetered air leaks into the motor. I would also clean the throttle body while you are in there. You can have this done at a professional shop. Good idea to check the crankcase vent valve also.
-Evan