Where can I find a "throttle kicker" for my 1986 c20 chevy truck?

I have been looking for this part for some time now with no luck, I was told I need it for the truck to pass smog. I've also heard it called a idle stopper, not sure which is right or if either are. I checked with the dealers and they cant get it because the truck is too old for the system now. And all the auto parts stores I've called say they don't have it. Where can I find a new one?
I already hit pick n' pull but it seems everyone has beat me to it.
Please help!

Look up LMC or classic industries.
do a search for parts suppliers for those trucks.
Do you mean an idle stop solenoid, or what exactly are you looking for?

Try LMC magazine my husband has a 84 chevy & orders all his parts from there.

Could be the 'idle solenoid' or 'idle cut-off valve' at JCW.
http://www.jcwhitney.com/carburetors-and-accessories/chevrolet-c20/c2039d50257j1s21.jcwx