According to Autoshop 101, carby cleaner works best in conjunction with a C02 sniffer up the bum as when this content increase, you have found your leak.
Also, I read that soapy water works better if you can seal off the air intake before the AFM, fix the throttle body plate wide open, and pressurize the intake using compressed air (to no more that 25psi). Then just spray and watch and listen....
- Course not every home garage is equiped to do this.....