popity pop pop on decel

[Dan Neuman <dneuman@stars.sfsu.edu>]

Hello All,
        When I let off the gas and am letting the engine slow the car 
down I get a small popcorny popping poppity pop pop out the exhaust that 
I have not got before..I think.  I belive that I have cured my vacuum leaks.
The only thing that I have done is adjust the idle mixture screws.  Which 
fuel system is suppliying fuel to the engine in this sit??  Is this a too lean
or to rich mixture case???
        thanks,
                Daniel 69 2000